Merge remote-tracking branch 'upstream/master' into packet-coalescing-core

.pylintrc

@@ -0,0 +1,38 @@
+[MESSAGES CONTROL]
+
+#TODO: Enable missing-docstring
+#TODO: Enable too-few-public-methods
+#TODO: Enable too-many-arguments
+#TODO: Enable no-init
+#TODO: Enable duplicate-code
+#TODO: Enable invalid-name
+#TODO: Enable suppressed-message
+#TODO: Enable locally-disabled
+#TODO: Enable protected-access
+#TODO: Enable no-name-in-module
+#TODO: Enable unused-argument
+#TODO: Enable fixme
+#TODO: Enable wrong-import-order
+#TODO: Enable no-value-for-parameter
+#TODO: Enable cyclic-import
+#TODO: Enable unused-variable
+#TODO: Enable redefined-outer-name
+#TODO: Enable unused-import
+#TODO: Enable too-many-instance-attributes
+#TODO: Enable broad-except
+#TODO: Enable too-many-locals
+#TODO: Enable too-many-lines
+#TODO: Enable redefined-variable-type
+#TODO: Enable next-method-called
+#TODO: Enable import-error
+#TODO: Enable useless-else-on-loop
+#TODO: Enable too-many-return-statements
+#TODO: Enable too-many-nested-blocks
+#TODO: Enable super-init-not-called
+#TODO: Enable simplifiable-if-statement
+#TODO: Enable no-self-use
+#TODO: Enable no-member
+#TODO: Enable logging-format-interpolation
+#TODO: Enable dangerous-default-value
+
+disable=missing-docstring,too-few-public-methods,too-many-arguments,no-init,duplicate-code,invalid-name,suppressed-message,locally-disabled,protected-access,no-name-in-module,unused-argument,fixme,wrong-import-order,no-value-for-parameter,cyclic-import,unused-variable,redefined-outer-name,unused-import,too-many-instance-attributes,broad-except,too-many-locals,too-many-lines,redefined-variable-type,next-method-called,import-error,useless-else-on-loop,too-many-return-statements,too-many-nested-blocks,super-init-not-called,simplifiable-if-statement,no-self-use,no-member,logging-format-interpolation,dangerous-default-value

BUILD

@@ -63,7 +63,7 @@ grpc_cc_library(
     deps = [
         "census",
         "grpc_base",
-        "grpc_lb_policy_grpclb",
+        "grpc_lb_policy_grpclb_secure",
         "grpc_lb_policy_pick_first",
         "grpc_lb_policy_round_robin",
         "grpc_load_reporting",
@@ -140,6 +140,7 @@ grpc_cc_library(
         "grpc++_base",
         "grpc++_codegen_base",
         "grpc++_codegen_base_src",
+        "grpc++_codegen_proto",
     ],
 )
 
@@ -284,9 +285,15 @@ grpc_cc_library(
         "src/core/ext/census/resource.h",
         "src/core/ext/census/rpc_metric_id.h",
         "src/core/ext/census/trace_context.h",
+        "src/core/ext/census/trace_label.h",
+        "src/core/ext/census/trace_propagation.h",
+        "src/core/ext/census/trace_status.h",
+        "src/core/ext/census/trace_string.h",
+        "src/core/ext/census/tracing.h",
     ],
     external_deps = [
         "nanopb",
+        "libssl",
     ],
     language = "c",
     public_hdrs = [
@@ -526,6 +533,7 @@ grpc_cc_library(
         "src/core/lib/transport/metadata.c",
         "src/core/lib/transport/metadata_batch.c",
         "src/core/lib/transport/pid_controller.c",
+        "src/core/lib/transport/bdp_estimator.c",
         "src/core/lib/transport/service_config.c",
         "src/core/lib/transport/static_metadata.c",
         "src/core/lib/transport/status_conversion.c",
@@ -623,9 +631,9 @@ grpc_cc_library(
         "src/core/lib/surface/completion_queue.h",
         "src/core/lib/surface/event_string.h",
         "src/core/lib/surface/init.h",
-        "src/core/lib/surface/validate_metadata.h",
         "src/core/lib/surface/lame_client.h",
         "src/core/lib/surface/server.h",
+        "src/core/lib/surface/validate_metadata.h",
         "src/core/lib/transport/byte_stream.h",
         "src/core/lib/transport/connectivity_state.h",
         "src/core/lib/transport/error_utils.h",
@@ -633,6 +641,7 @@ grpc_cc_library(
         "src/core/lib/transport/metadata.h",
         "src/core/lib/transport/metadata_batch.h",
         "src/core/lib/transport/pid_controller.h",
+        "src/core/lib/transport/bdp_estimator.h",
         "src/core/lib/transport/service_config.h",
         "src/core/lib/transport/static_metadata.h",
         "src/core/lib/transport/status_conversion.h",
@@ -663,7 +672,6 @@ grpc_cc_library(
 
 grpc_cc_library(
     name = "grpc_client_channel",
-    language = "c",
     srcs = [
         "src/core/ext/client_channel/channel_connectivity.c",
         "src/core/ext/client_channel/client_channel.c",
@@ -707,6 +715,7 @@ grpc_cc_library(
         "src/core/ext/client_channel/subchannel_index.h",
         "src/core/ext/client_channel/uri_parser.h",
     ],
+    language = "c",
     deps = [
         "grpc_base",
     ],
@@ -733,11 +742,13 @@ grpc_cc_library(
     name = "grpc_lb_policy_grpclb",
     srcs = [
         "src/core/ext/lb_policy/grpclb/grpclb.c",
+        "src/core/ext/lb_policy/grpclb/grpclb_channel.c",
         "src/core/ext/lb_policy/grpclb/load_balancer_api.c",
         "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c",
     ],
     hdrs = [
         "src/core/ext/lb_policy/grpclb/grpclb.h",
+        "src/core/ext/lb_policy/grpclb/grpclb_channel.h",
         "src/core/ext/lb_policy/grpclb/load_balancer_api.h",
         "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h",
     ],
@@ -751,6 +762,31 @@ grpc_cc_library(
     ],
 )
 
+grpc_cc_library(
+    name = "grpc_lb_policy_grpclb_secure",
+    srcs = [
+        "src/core/ext/lb_policy/grpclb/grpclb.c",
+        "src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c",
+        "src/core/ext/lb_policy/grpclb/load_balancer_api.c",
+        "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c",
+    ],
+    hdrs = [
+        "src/core/ext/lb_policy/grpclb/grpclb.h",
+        "src/core/ext/lb_policy/grpclb/grpclb_channel.h",
+        "src/core/ext/lb_policy/grpclb/load_balancer_api.h",
+        "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h",
+    ],
+    external_deps = [
+        "nanopb",
+    ],
+    language = "c",
+    deps = [
+        "grpc_base",
+        "grpc_client_channel",
+        "grpc_secure",
+    ],
+)
+
 grpc_cc_library(
     name = "grpc_lb_policy_pick_first",
     srcs = [
@@ -835,6 +871,7 @@ grpc_cc_library(
         "src/core/lib/security/credentials/ssl/ssl_credentials.c",
         "src/core/lib/security/transport/client_auth_filter.c",
         "src/core/lib/security/transport/secure_endpoint.c",
+        "src/core/lib/security/transport/lb_targets_info.c",
         "src/core/lib/security/transport/security_connector.c",
         "src/core/lib/security/transport/security_handshaker.c",
         "src/core/lib/security/transport/server_auth_filter.c",
@@ -858,6 +895,7 @@ grpc_cc_library(
         "src/core/lib/security/credentials/ssl/ssl_credentials.h",
         "src/core/lib/security/transport/auth_filters.h",
         "src/core/lib/security/transport/secure_endpoint.h",
+        "src/core/lib/security/transport/lb_targets_info.h",
         "src/core/lib/security/transport/security_connector.h",
         "src/core/lib/security/transport/security_handshaker.h",
         "src/core/lib/security/transport/tsi_error.h",
@@ -941,22 +979,21 @@ grpc_cc_library(
 )
 
 grpc_cc_library(
-  name = "grpc_transport_chttp2_client_connector",
-  hdrs = [
-   "src/core/ext/transport/chttp2/client/chttp2_connector.h",
-  ],
-  srcs = [
-   "src/core/ext/transport/chttp2/client/chttp2_connector.c",
-  ],
-  language = "c",
-  deps = [
-   "grpc_transport_chttp2",
-   "grpc_base",
-   "grpc_client_channel",
-  ],
+    name = "grpc_transport_chttp2_client_connector",
+    srcs = [
+        "src/core/ext/transport/chttp2/client/chttp2_connector.c",
+    ],
+    hdrs = [
+        "src/core/ext/transport/chttp2/client/chttp2_connector.h",
+    ],
+    language = "c",
+    deps = [
+        "grpc_base",
+        "grpc_client_channel",
+        "grpc_transport_chttp2",
+    ],
 )
 
-
 grpc_cc_library(
     name = "grpc_transport_chttp2_client_insecure",
     srcs = [

Makefile

@@ -212,6 +212,14 @@ CPPFLAGS_mutrace = -O3 -fno-omit-frame-pointer
 LDFLAGS_mutrace = -rdynamic
 DEFINES_mutrace = NDEBUG
 
+VALID_CONFIG_counters = 1
+CC_counters = $(DEFAULT_CC)
+CXX_counters = $(DEFAULT_CXX)
+LD_counters = $(DEFAULT_CC)
+LDXX_counters = $(DEFAULT_CXX)
+CPPFLAGS_counters = -O2 -DGPR_MU_COUNTERS
+DEFINES_counters = NDEBUG
+
 
 
 # General settings.
@@ -320,7 +328,7 @@ CXXFLAGS += -std=c++11
 else
 CXXFLAGS += -std=c++0x
 endif
-CPPFLAGS += -g -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter
+CPPFLAGS += -g -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter -DOSATOMIC_USE_INLINED=1
 LDFLAGS += -g
 
 CPPFLAGS += $(CPPFLAGS_$(CONFIG))
@@ -899,6 +907,7 @@ alloc_test: $(BINDIR)/$(CONFIG)/alloc_test
 alpn_test: $(BINDIR)/$(CONFIG)/alpn_test
 api_fuzzer: $(BINDIR)/$(CONFIG)/api_fuzzer
 bad_server_response_test: $(BINDIR)/$(CONFIG)/bad_server_response_test
+bdp_estimator_test: $(BINDIR)/$(CONFIG)/bdp_estimator_test
 bin_decoder_test: $(BINDIR)/$(CONFIG)/bin_decoder_test
 bin_encoder_test: $(BINDIR)/$(CONFIG)/bin_encoder_test
 census_context_test: $(BINDIR)/$(CONFIG)/census_context_test
@@ -997,6 +1006,7 @@ no_server_test: $(BINDIR)/$(CONFIG)/no_server_test
 percent_decode_fuzzer: $(BINDIR)/$(CONFIG)/percent_decode_fuzzer
 percent_encode_fuzzer: $(BINDIR)/$(CONFIG)/percent_encode_fuzzer
 percent_encoding_test: $(BINDIR)/$(CONFIG)/percent_encoding_test
+pollset_set_test: $(BINDIR)/$(CONFIG)/pollset_set_test
 resolve_address_posix_test: $(BINDIR)/$(CONFIG)/resolve_address_posix_test
 resolve_address_test: $(BINDIR)/$(CONFIG)/resolve_address_test
 resource_quota_test: $(BINDIR)/$(CONFIG)/resource_quota_test
@@ -1071,6 +1081,7 @@ metrics_client: $(BINDIR)/$(CONFIG)/metrics_client
 mock_test: $(BINDIR)/$(CONFIG)/mock_test
 noop-benchmark: $(BINDIR)/$(CONFIG)/noop-benchmark
 proto_server_reflection_test: $(BINDIR)/$(CONFIG)/proto_server_reflection_test
+proto_utils_test: $(BINDIR)/$(CONFIG)/proto_utils_test
 qps_interarrival_test: $(BINDIR)/$(CONFIG)/qps_interarrival_test
 qps_json_driver: $(BINDIR)/$(CONFIG)/qps_json_driver
 qps_openloop_test: $(BINDIR)/$(CONFIG)/qps_openloop_test
@@ -1090,6 +1101,7 @@ streaming_throughput_test: $(BINDIR)/$(CONFIG)/streaming_throughput_test
 stress_test: $(BINDIR)/$(CONFIG)/stress_test
 thread_manager_test: $(BINDIR)/$(CONFIG)/thread_manager_test
 thread_stress_test: $(BINDIR)/$(CONFIG)/thread_stress_test
+writes_per_rpc_test: $(BINDIR)/$(CONFIG)/writes_per_rpc_test
 public_headers_must_be_c89: $(BINDIR)/$(CONFIG)/public_headers_must_be_c89
 boringssl_aes_test: $(BINDIR)/$(CONFIG)/boringssl_aes_test
 boringssl_asn1_test: $(BINDIR)/$(CONFIG)/boringssl_asn1_test
@@ -1259,6 +1271,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/alloc_test \
   $(BINDIR)/$(CONFIG)/alpn_test \
   $(BINDIR)/$(CONFIG)/bad_server_response_test \
+  $(BINDIR)/$(CONFIG)/bdp_estimator_test \
   $(BINDIR)/$(CONFIG)/bin_decoder_test \
   $(BINDIR)/$(CONFIG)/bin_encoder_test \
   $(BINDIR)/$(CONFIG)/census_context_test \
@@ -1341,6 +1354,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/murmur_hash_test \
   $(BINDIR)/$(CONFIG)/no_server_test \
   $(BINDIR)/$(CONFIG)/percent_encoding_test \
+  $(BINDIR)/$(CONFIG)/pollset_set_test \
   $(BINDIR)/$(CONFIG)/resolve_address_posix_test \
   $(BINDIR)/$(CONFIG)/resolve_address_test \
   $(BINDIR)/$(CONFIG)/resource_quota_test \
@@ -1466,6 +1480,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/mock_test \
   $(BINDIR)/$(CONFIG)/noop-benchmark \
   $(BINDIR)/$(CONFIG)/proto_server_reflection_test \
+  $(BINDIR)/$(CONFIG)/proto_utils_test \
   $(BINDIR)/$(CONFIG)/qps_interarrival_test \
   $(BINDIR)/$(CONFIG)/qps_json_driver \
   $(BINDIR)/$(CONFIG)/qps_openloop_test \
@@ -1485,6 +1500,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/stress_test \
   $(BINDIR)/$(CONFIG)/thread_manager_test \
   $(BINDIR)/$(CONFIG)/thread_stress_test \
+  $(BINDIR)/$(CONFIG)/writes_per_rpc_test \
   $(BINDIR)/$(CONFIG)/boringssl_aes_test \
   $(BINDIR)/$(CONFIG)/boringssl_asn1_test \
   $(BINDIR)/$(CONFIG)/boringssl_base64_test \
@@ -1568,6 +1584,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/mock_test \
   $(BINDIR)/$(CONFIG)/noop-benchmark \
   $(BINDIR)/$(CONFIG)/proto_server_reflection_test \
+  $(BINDIR)/$(CONFIG)/proto_utils_test \
   $(BINDIR)/$(CONFIG)/qps_interarrival_test \
   $(BINDIR)/$(CONFIG)/qps_json_driver \
   $(BINDIR)/$(CONFIG)/qps_openloop_test \
@@ -1587,6 +1604,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/stress_test \
   $(BINDIR)/$(CONFIG)/thread_manager_test \
   $(BINDIR)/$(CONFIG)/thread_stress_test \
+  $(BINDIR)/$(CONFIG)/writes_per_rpc_test \
 
 endif
 
@@ -1606,6 +1624,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/alpn_test || ( echo test alpn_test failed ; exit 1 )
 	$(E) "[RUN]     Testing bad_server_response_test"
 	$(Q) $(BINDIR)/$(CONFIG)/bad_server_response_test || ( echo test bad_server_response_test failed ; exit 1 )
+	$(E) "[RUN]     Testing bdp_estimator_test"
+	$(Q) $(BINDIR)/$(CONFIG)/bdp_estimator_test || ( echo test bdp_estimator_test failed ; exit 1 )
 	$(E) "[RUN]     Testing bin_decoder_test"
 	$(Q) $(BINDIR)/$(CONFIG)/bin_decoder_test || ( echo test bin_decoder_test failed ; exit 1 )
 	$(E) "[RUN]     Testing bin_encoder_test"
@@ -1748,6 +1768,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/no_server_test || ( echo test no_server_test failed ; exit 1 )
 	$(E) "[RUN]     Testing percent_encoding_test"
 	$(Q) $(BINDIR)/$(CONFIG)/percent_encoding_test || ( echo test percent_encoding_test failed ; exit 1 )
+	$(E) "[RUN]     Testing pollset_set_test"
+	$(Q) $(BINDIR)/$(CONFIG)/pollset_set_test || ( echo test pollset_set_test failed ; exit 1 )
 	$(E) "[RUN]     Testing resolve_address_posix_test"
 	$(Q) $(BINDIR)/$(CONFIG)/resolve_address_posix_test || ( echo test resolve_address_posix_test failed ; exit 1 )
 	$(E) "[RUN]     Testing resolve_address_test"
@@ -1894,6 +1916,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/noop-benchmark || ( echo test noop-benchmark failed ; exit 1 )
 	$(E) "[RUN]     Testing proto_server_reflection_test"
 	$(Q) $(BINDIR)/$(CONFIG)/proto_server_reflection_test || ( echo test proto_server_reflection_test failed ; exit 1 )
+	$(E) "[RUN]     Testing proto_utils_test"
+	$(Q) $(BINDIR)/$(CONFIG)/proto_utils_test || ( echo test proto_utils_test failed ; exit 1 )
 	$(E) "[RUN]     Testing qps_openloop_test"
 	$(Q) $(BINDIR)/$(CONFIG)/qps_openloop_test || ( echo test qps_openloop_test failed ; exit 1 )
 	$(E) "[RUN]     Testing round_robin_end2end_test"
@@ -1918,6 +1942,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/thread_manager_test || ( echo test thread_manager_test failed ; exit 1 )
 	$(E) "[RUN]     Testing thread_stress_test"
 	$(Q) $(BINDIR)/$(CONFIG)/thread_stress_test || ( echo test thread_stress_test failed ; exit 1 )
+	$(E) "[RUN]     Testing writes_per_rpc_test"
+	$(Q) $(BINDIR)/$(CONFIG)/writes_per_rpc_test || ( echo test writes_per_rpc_test failed ; exit 1 )
 
 
 flaky_test_cxx: buildtests_cxx
@@ -2729,6 +2755,7 @@ LIBGRPC_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -2779,6 +2806,7 @@ LIBGRPC_SRC = \
     src/core/lib/security/credentials/plugin/plugin_credentials.c \
     src/core/lib/security/credentials/ssl/ssl_credentials.c \
     src/core/lib/security/transport/client_auth_filter.c \
+    src/core/lib/security/transport/lb_targets_info.c \
     src/core/lib/security/transport/secure_endpoint.c \
     src/core/lib/security/transport/security_connector.c \
     src/core/lib/security/transport/security_handshaker.c \
@@ -2819,6 +2847,7 @@ LIBGRPC_SRC = \
     src/core/ext/transport/chttp2/client/insecure/channel_create.c \
     src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c \
     src/core/ext/lb_policy/grpclb/grpclb.c \
+    src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c \
     src/core/ext/lb_policy/grpclb/load_balancer_api.c \
     src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c \
     third_party/nanopb/pb_common.c \
@@ -3037,6 +3066,7 @@ LIBGRPC_CRONET_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -3111,6 +3141,7 @@ LIBGRPC_CRONET_SRC = \
     src/core/lib/security/credentials/plugin/plugin_credentials.c \
     src/core/lib/security/credentials/ssl/ssl_credentials.c \
     src/core/lib/security/transport/client_auth_filter.c \
+    src/core/lib/security/transport/lb_targets_info.c \
     src/core/lib/security/transport/secure_endpoint.c \
     src/core/lib/security/transport/security_connector.c \
     src/core/lib/security/transport/security_handshaker.c \
@@ -3220,6 +3251,7 @@ LIBGRPC_TEST_UTIL_SRC = \
     test/core/end2end/fixtures/http_proxy.c \
     test/core/end2end/fixtures/proxy.c \
     test/core/iomgr/endpoint_tests.c \
+    test/core/util/debugger_macros.c \
     test/core/util/grpc_profiler.c \
     test/core/util/memory_counters.c \
     test/core/util/mock_endpoint.c \
@@ -3335,6 +3367,7 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -3418,6 +3451,7 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     test/core/end2end/fixtures/http_proxy.c \
     test/core/end2end/fixtures/proxy.c \
     test/core/iomgr/endpoint_tests.c \
+    test/core/util/debugger_macros.c \
     test/core/util/grpc_profiler.c \
     test/core/util/memory_counters.c \
     test/core/util/mock_endpoint.c \
@@ -3559,6 +3593,7 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -3624,6 +3659,7 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/load_reporting/load_reporting.c \
     src/core/ext/load_reporting/load_reporting_filter.c \
     src/core/ext/lb_policy/grpclb/grpclb.c \
+    src/core/ext/lb_policy/grpclb/grpclb_channel.c \
     src/core/ext/lb_policy/grpclb/load_balancer_api.c \
     src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c \
     third_party/nanopb/pb_common.c \
@@ -3924,6 +3960,8 @@ PUBLIC_HEADERS_CXX += \
     include/grpc/impl/codegen/sync_generic.h \
     include/grpc/impl/codegen/sync_posix.h \
     include/grpc/impl/codegen/sync_windows.h \
+    include/grpc++/impl/codegen/proto_utils.h \
+    include/grpc++/impl/codegen/config_protobuf.h \
 
 LIBGRPC++_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGRPC++_SRC))))
 
@@ -4150,6 +4188,7 @@ LIBGRPC++_CRONET_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -7965,6 +8004,38 @@ endif
 endif
 
 
+BDP_ESTIMATOR_TEST_SRC = \
+    test/core/transport/bdp_estimator_test.c \
+
+BDP_ESTIMATOR_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(BDP_ESTIMATOR_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/bdp_estimator_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/bdp_estimator_test: $(BDP_ESTIMATOR_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(BDP_ESTIMATOR_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/bdp_estimator_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/transport/bdp_estimator_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_bdp_estimator_test: $(BDP_ESTIMATOR_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(BDP_ESTIMATOR_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 BIN_DECODER_TEST_SRC = \
     test/core/transport/chttp2/bin_decoder_test.c \
 
@@ -11101,6 +11172,38 @@ endif
 endif
 
 
+POLLSET_SET_TEST_SRC = \
+    test/core/iomgr/pollset_set_test.c \
+
+POLLSET_SET_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(POLLSET_SET_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/pollset_set_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/pollset_set_test: $(POLLSET_SET_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(POLLSET_SET_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/pollset_set_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/iomgr/pollset_set_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_pollset_set_test: $(POLLSET_SET_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(POLLSET_SET_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 RESOLVE_ADDRESS_POSIX_TEST_SRC = \
     test/core/iomgr/resolve_address_posix_test.c \
 
@@ -13859,6 +13962,49 @@ endif
 endif
 
 
+PROTO_UTILS_TEST_SRC = \
+    test/cpp/codegen/proto_utils_test.cc \
+
+PROTO_UTILS_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(PROTO_UTILS_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/proto_utils_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/proto_utils_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/proto_utils_test: $(PROTOBUF_DEP) $(PROTO_UTILS_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(PROTO_UTILS_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/proto_utils_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/codegen/proto_utils_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a
+
+deps_proto_utils_test: $(PROTO_UTILS_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(PROTO_UTILS_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 QPS_INTERARRIVAL_TEST_SRC = \
     test/cpp/qps/qps_interarrival_test.cc \
 
@@ -14725,6 +14871,49 @@ endif
 endif
 
 
+WRITES_PER_RPC_TEST_SRC = \
+    test/cpp/performance/writes_per_rpc_test.cc \
+
+WRITES_PER_RPC_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(WRITES_PER_RPC_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/writes_per_rpc_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/writes_per_rpc_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/writes_per_rpc_test: $(PROTOBUF_DEP) $(WRITES_PER_RPC_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(WRITES_PER_RPC_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/writes_per_rpc_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/performance/writes_per_rpc_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_writes_per_rpc_test: $(WRITES_PER_RPC_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(WRITES_PER_RPC_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 PUBLIC_HEADERS_MUST_BE_C89_SRC = \
     test/core/surface/public_headers_must_be_c89.c \
 
@@ -17566,6 +17755,7 @@ ifneq ($(OPENSSL_DEP),)
 # This is to ensure the embedded OpenSSL is built beforehand, properly
 # installing headers to their final destination on the drive. We need this
 # otherwise parallel compilation will fail if a source is compiled first.
+src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c: $(OPENSSL_DEP)
 src/core/ext/transport/chttp2/client/secure/secure_channel_create.c: $(OPENSSL_DEP)
 src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c: $(OPENSSL_DEP)
 src/core/ext/transport/cronet/client/secure/cronet_channel_create.c: $(OPENSSL_DEP)
@@ -17587,6 +17777,7 @@ src/core/lib/security/credentials/oauth2/oauth2_credentials.c: $(OPENSSL_DEP)
 src/core/lib/security/credentials/plugin/plugin_credentials.c: $(OPENSSL_DEP)
 src/core/lib/security/credentials/ssl/ssl_credentials.c: $(OPENSSL_DEP)
 src/core/lib/security/transport/client_auth_filter.c: $(OPENSSL_DEP)
+src/core/lib/security/transport/lb_targets_info.c: $(OPENSSL_DEP)
 src/core/lib/security/transport/secure_endpoint.c: $(OPENSSL_DEP)
 src/core/lib/security/transport/security_connector.c: $(OPENSSL_DEP)
 src/core/lib/security/transport/security_handshaker.c: $(OPENSSL_DEP)

binding.gyp

@@ -707,6 +707,7 @@
         'src/core/lib/surface/server.c',
         'src/core/lib/surface/validate_metadata.c',
         'src/core/lib/surface/version.c',
+        'src/core/lib/transport/bdp_estimator.c',
         'src/core/lib/transport/byte_stream.c',
         'src/core/lib/transport/connectivity_state.c',
         'src/core/lib/transport/error_utils.c',
@@ -757,6 +758,7 @@
         'src/core/lib/security/credentials/plugin/plugin_credentials.c',
         'src/core/lib/security/credentials/ssl/ssl_credentials.c',
         'src/core/lib/security/transport/client_auth_filter.c',
+        'src/core/lib/security/transport/lb_targets_info.c',
         'src/core/lib/security/transport/secure_endpoint.c',
         'src/core/lib/security/transport/security_connector.c',
         'src/core/lib/security/transport/security_handshaker.c',
@@ -797,6 +799,7 @@
         'src/core/ext/transport/chttp2/client/insecure/channel_create.c',
         'src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c',
         'src/core/ext/lb_policy/grpclb/grpclb.c',
+        'src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c',
         'src/core/ext/lb_policy/grpclb/load_balancer_api.c',
         'src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c',
         'third_party/nanopb/pb_common.c',

build.yaml

@@ -31,6 +31,11 @@ filegroups:
   - src/core/ext/census/resource.h
   - src/core/ext/census/rpc_metric_id.h
   - src/core/ext/census/trace_context.h
+  - src/core/ext/census/trace_label.h
+  - src/core/ext/census/trace_propagation.h
+  - src/core/ext/census/trace_status.h
+  - src/core/ext/census/trace_string.h
+  - src/core/ext/census/tracing.h
   src:
   - src/core/ext/census/base_resources.c
   - src/core/ext/census/context.c
@@ -256,6 +261,7 @@ filegroups:
   - src/core/lib/surface/lame_client.h
   - src/core/lib/surface/server.h
   - src/core/lib/surface/validate_metadata.h
+  - src/core/lib/transport/bdp_estimator.h
   - src/core/lib/transport/byte_stream.h
   - src/core/lib/transport/connectivity_state.h
   - src/core/lib/transport/error_utils.h
@@ -375,6 +381,7 @@ filegroups:
   - src/core/lib/surface/server.c
   - src/core/lib/surface/validate_metadata.c
   - src/core/lib/surface/version.c
+  - src/core/lib/transport/bdp_estimator.c
   - src/core/lib/transport/byte_stream.c
   - src/core/lib/transport/connectivity_state.c
   - src/core/lib/transport/error_utils.c
@@ -450,10 +457,28 @@ filegroups:
 - name: grpc_lb_policy_grpclb
   headers:
   - src/core/ext/lb_policy/grpclb/grpclb.h
+  - src/core/ext/lb_policy/grpclb/grpclb_channel.h
   - src/core/ext/lb_policy/grpclb/load_balancer_api.h
   - src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h
   src:
   - src/core/ext/lb_policy/grpclb/grpclb.c
+  - src/core/ext/lb_policy/grpclb/grpclb_channel.c
+  - src/core/ext/lb_policy/grpclb/load_balancer_api.c
+  - src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
+  plugin: grpc_lb_policy_grpclb
+  uses:
+  - grpc_base
+  - grpc_client_channel
+  - nanopb
+- name: grpc_lb_policy_grpclb_secure
+  headers:
+  - src/core/ext/lb_policy/grpclb/grpclb.h
+  - src/core/ext/lb_policy/grpclb/grpclb_channel.h
+  - src/core/ext/lb_policy/grpclb/load_balancer_api.h
+  - src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h
+  src:
+  - src/core/ext/lb_policy/grpclb/grpclb.c
+  - src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c
   - src/core/ext/lb_policy/grpclb/load_balancer_api.c
   - src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
   plugin: grpc_lb_policy_grpclb
@@ -516,6 +541,7 @@ filegroups:
   - src/core/lib/security/credentials/plugin/plugin_credentials.h
   - src/core/lib/security/credentials/ssl/ssl_credentials.h
   - src/core/lib/security/transport/auth_filters.h
+  - src/core/lib/security/transport/lb_targets_info.h
   - src/core/lib/security/transport/secure_endpoint.h
   - src/core/lib/security/transport/security_connector.h
   - src/core/lib/security/transport/security_handshaker.h
@@ -539,6 +565,7 @@ filegroups:
   - src/core/lib/security/credentials/plugin/plugin_credentials.c
   - src/core/lib/security/credentials/ssl/ssl_credentials.c
   - src/core/lib/security/transport/client_auth_filter.c
+  - src/core/lib/security/transport/lb_targets_info.c
   - src/core/lib/security/transport/secure_endpoint.c
   - src/core/lib/security/transport/security_connector.c
   - src/core/lib/security/transport/security_handshaker.c
@@ -560,6 +587,7 @@ filegroups:
   - test/core/end2end/fixtures/http_proxy.h
   - test/core/end2end/fixtures/proxy.h
   - test/core/iomgr/endpoint_tests.h
+  - test/core/util/debugger_macros.h
   - test/core/util/grpc_profiler.h
   - test/core/util/memory_counters.h
   - test/core/util/mock_endpoint.h
@@ -574,6 +602,7 @@ filegroups:
   - test/core/end2end/fixtures/http_proxy.c
   - test/core/end2end/fixtures/proxy.c
   - test/core/iomgr/endpoint_tests.c
+  - test/core/util/debugger_macros.c
   - test/core/util/grpc_profiler.c
   - test/core/util/memory_counters.c
   - test/core/util/mock_endpoint.c
@@ -906,7 +935,7 @@ libs:
   - grpc_transport_chttp2_client_secure
   - grpc_transport_chttp2_server_insecure
   - grpc_transport_chttp2_client_insecure
-  - grpc_lb_policy_grpclb
+  - grpc_lb_policy_grpclb_secure
   - grpc_lb_policy_pick_first
   - grpc_lb_policy_round_robin
   - grpc_resolver_dns_native
@@ -1060,6 +1089,7 @@ libs:
   filegroups:
   - grpc++_base
   - grpc++_codegen_base
+  - grpc++_codegen_proto
   - grpc++_codegen_base_src
   secure: check
   vs_project_guid: '{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}'
@@ -1441,6 +1471,16 @@ targets:
   - gpr
   exclude_iomgrs:
   - uv
+- name: bdp_estimator_test
+  build: test
+  language: c
+  src:
+  - test/core/transport/bdp_estimator_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: bin_decoder_test
   build: test
   language: c
@@ -2491,6 +2531,20 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: pollset_set_test
+  build: test
+  language: c
+  src:
+  - test/core/iomgr/pollset_set_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+  exclude_iomgrs:
+  - uv
+  platforms:
+  - linux
 - name: resolve_address_posix_test
   build: test
   language: c
@@ -2944,6 +2998,12 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+  args:
+  - --benchmark_min_time=0
+  platforms:
+  - mac
+  - linux
+  - posix
 - name: channel_arguments_test
   gtest: true
   build: test
@@ -3370,6 +3430,10 @@ targets:
   - gpr_test_util
   - gpr
   - grpc++_test_config
+  platforms:
+  - mac
+  - linux
+  - posix
 - name: metrics_client
   build: test
   run: false
@@ -3419,6 +3483,18 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: proto_utils_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/cpp/codegen/proto_utils_test.cc
+  deps:
+  - grpc++
+  - grpc
+  filegroups:
+  - grpc++_codegen_base
+  - grpc++_codegen_proto
 - name: qps_interarrival_test
   build: test
   run: false
@@ -3718,6 +3794,24 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: writes_per_rpc_test
+  gtest: true
+  cpu_cost: 0.5
+  build: test
+  language: c++
+  src:
+  - test/cpp/performance/writes_per_rpc_test.cc
+  deps:
+  - grpc++_test_util
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
+  platforms:
+  - mac
+  - linux
+  - posix
 - name: public_headers_must_be_c89
   build: test
   language: c89
@@ -3784,6 +3878,9 @@ configs:
   basicprof:
     CPPFLAGS: -O2 -DGRPC_BASIC_PROFILER -DGRPC_TIMERS_RDTSC
     DEFINES: NDEBUG
+  counters:
+    CPPFLAGS: -O2 -DGPR_MU_COUNTERS
+    DEFINES: NDEBUG
   dbg:
     CPPFLAGS: -O0
     DEFINES: _DEBUG DEBUG
@@ -3860,7 +3957,7 @@ defaults:
     CPPFLAGS: -Ithird_party/boringssl/include -fvisibility=hidden -DOPENSSL_NO_ASM
       -D_GNU_SOURCE -DWIN32_LEAN_AND_MEAN -D_HAS_EXCEPTIONS=0 -DNOMINMAX
   global:
-    CPPFLAGS: -g -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter
+    CPPFLAGS: -g -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter -DOSATOMIC_USE_INLINED=1
     LDFLAGS: -g
   zlib:
     CFLAGS: -Wno-sign-conversion -Wno-conversion -Wno-unused-value -Wno-implicit-function-declaration

cmake/msvc_static_runtime.cmake

@@ -0,0 +1,14 @@
+option(gRPC_MSVC_STATIC_RUNTIME "Link with static msvc runtime libraries" OFF)
+
+if(gRPC_MSVC_STATIC_RUNTIME)
+  # switch from dynamic to static linking of msvcrt
+  foreach(flag_var
+    CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+    CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+
+    if(${flag_var} MATCHES "/MD")
+    string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
+    endif(${flag_var} MATCHES "/MD")
+  endforeach(flag_var)
+endif()
+

composer.json

@@ -7,7 +7,7 @@
   "license": "BSD-3-Clause",
   "require": {
     "php": ">=5.5.0",
-    "google/protobuf": "v3.1.0-alpha-1"
+    "google/protobuf": "v3.1.0"
   },
   "require-dev": {
     "google/auth": "v0.9"

config.m4

@@ -186,6 +186,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -236,6 +237,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/security/credentials/plugin/plugin_credentials.c \
     src/core/lib/security/credentials/ssl/ssl_credentials.c \
     src/core/lib/security/transport/client_auth_filter.c \
+    src/core/lib/security/transport/lb_targets_info.c \
     src/core/lib/security/transport/secure_endpoint.c \
     src/core/lib/security/transport/security_connector.c \
     src/core/lib/security/transport/security_handshaker.c \
@@ -276,6 +278,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/transport/chttp2/client/insecure/channel_create.c \
     src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c \
     src/core/ext/lb_policy/grpclb/grpclb.c \
+    src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c \
     src/core/ext/lb_policy/grpclb/load_balancer_api.c \
     src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c \
     third_party/nanopb/pb_common.c \

doc/PROTOCOL-WEB.md

@@ -60,21 +60,22 @@ HTTP/2 related behavior (specified in [gRPC over HTTP2](http://www.grpc.io/docs/
 Message framing (vs. [http2-transport-mapping](http://www.grpc.io/docs/guides/wire.html#http2-transport-mapping))
 
 1. Response status encoded as part of the response body
-  * Key-value pairs encoded in the HTTP/2 [literal header format](https://tools.ietf.org/html/rfc7541#section-6.2) as a single header block.
+  * Key-value pairs encoded as a HTTP/1 headers block (without the terminating newline).
 2. 8th (MSB) bit of the 1st gRPC frame byte
   * 0: data
   * 1: trailers
 3. Trailers must be the last message of the response, as enforced
 by the implementation
 4. Trailers-only responses: no change to the gRPC protocol spec.
-Trailers will be sent together with response headers, with no message
+Trailers may be sent together with response headers, with no message
 in the body.
 
 ---
 
-User Agent
+User Agent and Server headers
 
-* grpc-web-javascript/0.1
+* U-A: grpc-web-javascript/0.1
+* Server: grpc-web-gateway/0.1
 
 ---
 

doc/environment_variables.md

@@ -35,6 +35,8 @@ some configuration as environment variables that can be set.
   A comma separated list of tracers that provide additional insight into how
   gRPC C core is processing requests via debug logs. Available tracers include:
   - api - traces api calls to the C core
+  - bdp_estimator - traces behavior of bdp estimation logic
+  - call_error - traces the possible errors contributing to final call status
   - channel - traces operations on the C core channel stack
   - combiner - traces combiner lock state
   - compression - traces compression operations
@@ -55,10 +57,10 @@ some configuration as environment variables that can be set.
   - secure_endpoint - traces bytes flowing through encrypted channels
   - transport_security - traces metadata about secure channel establishment
   - tcp - traces bytes in and out of a channel
-  
+
   'all' can additionally be used to turn all traces on.
   Individual traces can be disabled by prefixing them with '-'.
- 
+
   Example:
   export GRPC_TRACE=all,-pending_tags
 

examples/csharp/helloworld/generate_protos.bat

@@ -34,7 +34,7 @@ setlocal
 @rem enter this directory
 cd /d %~dp0
 
-set TOOLS_PATH=packages\Grpc.Tools.1.0.0\tools\windows_x86
+set TOOLS_PATH=packages\Grpc.Tools.1.0.1\tools\windows_x86
 
 %TOOLS_PATH%\protoc.exe -I../../protos --csharp_out Greeter  ../../protos/helloworld.proto --grpc_out Greeter --plugin=protoc-gen-grpc=%TOOLS_PATH%\grpc_csharp_plugin.exe
 

examples/php/composer.json

@@ -2,7 +2,11 @@
   "name": "grpc/grpc-demo",
   "description": "gRPC example for PHP",
   "require": {
-    "ext-grpc": "*",
-    "grpc/grpc": "v1.0.0"
+    "grpc/grpc": "v1.1.0"
+  },
+  "autoload": {
+    "psr-4": {
+      "": "route_guide/"
+    }
   }
 }

examples/php/greeter_client.php

@@ -33,14 +33,18 @@
  */
 
 require dirname(__FILE__).'/vendor/autoload.php';
-require dirname(__FILE__).'/helloworld.php';
+
+// The following includes are needed when using protobuf 3.1.0
+// and will suppress warnings when using protobuf 3.2.0+
+@include_once dirname(__FILE__).'/helloworld.pb.php';
+@include_once dirname(__FILE__).'/helloworld_grpc_pb.php';
 
 function greet($name)
 {
-    $client = new helloworld\GreeterClient('localhost:50051', [
+    $client = new Helloworld\GreeterClient('localhost:50051', [
         'credentials' => Grpc\ChannelCredentials::createInsecure(),
     ]);
-    $request = new helloworld\HelloRequest();
+    $request = new Helloworld\HelloRequest();
     $request->setName($name);
     list($reply, $status) = $client->SayHello($request)->wait();
     $message = $reply->getMessage();

examples/php/helloworld.pb.php

@@ -0,0 +1,58 @@
+<?php
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: helloworld.proto
+
+namespace Helloworld;
+
+use Google\Protobuf\Internal\DescriptorPool;
+use Google\Protobuf\Internal\GPBType;
+use Google\Protobuf\Internal\RepeatedField;
+use Google\Protobuf\Internal\GPBUtil;
+
+class HelloRequest extends \Google\Protobuf\Internal\Message
+{
+    private $name = '';
+
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    public function setName($var)
+    {
+        GPBUtil::checkString($var, True);
+        $this->name = $var;
+    }
+
+}
+
+class HelloReply extends \Google\Protobuf\Internal\Message
+{
+    private $message = '';
+
+    public function getMessage()
+    {
+        return $this->message;
+    }
+
+    public function setMessage($var)
+    {
+        GPBUtil::checkString($var, True);
+        $this->message = $var;
+    }
+
+}
+
+$pool = DescriptorPool::getGeneratedPool();
+
+$pool->internalAddGeneratedFile(hex2bin(
+    "0ae6010a1068656c6c6f776f726c642e70726f746f120a68656c6c6f776f" .
+    "726c64221c0a0c48656c6c6f52657175657374120c0a046e616d65180120" .
+    "012809221d0a0a48656c6c6f5265706c79120f0a076d6573736167651801" .
+    "2001280932490a0747726565746572123e0a0853617948656c6c6f12182e" .
+    "68656c6c6f776f726c642e48656c6c6f526571756573741a162e68656c6c" .
+    "6f776f726c642e48656c6c6f5265706c79220042360a1b696f2e67727063" .
+    "2e6578616d706c65732e68656c6c6f776f726c64420f48656c6c6f576f72" .
+    "6c6450726f746f5001a20203484c57620670726f746f33"
+));
+

examples/php/helloworld.php

@@ -1,168 +0,0 @@
-<?php
-// DO NOT EDIT! Generated by Protobuf-PHP protoc plugin 1.0
-// Source: helloworld.proto
-//   Date: 2015-09-24 20:40:14
-
-namespace helloworld {
-
-  class HelloRequest extends \DrSlump\Protobuf\Message
-  {
-      /**  @var string */
-    public $name = null;
-
-    /** @var \Closure[] */
-    protected static $__extensions = array();
-
-      public static function descriptor()
-      {
-          $descriptor = new \DrSlump\Protobuf\Descriptor(__CLASS__, 'helloworld.HelloRequest');
-
-      // OPTIONAL STRING name = 1
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 1;
-          $f->name = 'name';
-          $f->type = \DrSlump\Protobuf::TYPE_STRING;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $descriptor->addField($f);
-
-          foreach (self::$__extensions as $cb) {
-              $descriptor->addField($cb(), true);
-          }
-
-          return $descriptor;
-      }
-
-    /**
-     * Check if <name> has a value.
-     *
-     * @return bool
-     */
-    public function hasName()
-    {
-        return $this->_has(1);
-    }
-
-    /**
-     * Clear <name> value.
-     *
-     * @return \helloworld\HelloRequest
-     */
-    public function clearName()
-    {
-        return $this->_clear(1);
-    }
-
-    /**
-     * Get <name> value.
-     *
-     * @return string
-     */
-    public function getName()
-    {
-        return $this->_get(1);
-    }
-
-    /**
-     * Set <name> value.
-     *
-     * @param string $value
-     *
-     * @return \helloworld\HelloRequest
-     */
-    public function setName($value)
-    {
-        return $this->_set(1, $value);
-    }
-  }
-}
-
-namespace helloworld {
-
-  class HelloReply extends \DrSlump\Protobuf\Message
-  {
-      /**  @var string */
-    public $message = null;
-
-    /** @var \Closure[] */
-    protected static $__extensions = array();
-
-      public static function descriptor()
-      {
-          $descriptor = new \DrSlump\Protobuf\Descriptor(__CLASS__, 'helloworld.HelloReply');
-
-      // OPTIONAL STRING message = 1
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 1;
-          $f->name = 'message';
-          $f->type = \DrSlump\Protobuf::TYPE_STRING;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $descriptor->addField($f);
-
-          foreach (self::$__extensions as $cb) {
-              $descriptor->addField($cb(), true);
-          }
-
-          return $descriptor;
-      }
-
-    /**
-     * Check if <message> has a value.
-     *
-     * @return bool
-     */
-    public function hasMessage()
-    {
-        return $this->_has(1);
-    }
-
-    /**
-     * Clear <message> value.
-     *
-     * @return \helloworld\HelloReply
-     */
-    public function clearMessage()
-    {
-        return $this->_clear(1);
-    }
-
-    /**
-     * Get <message> value.
-     *
-     * @return string
-     */
-    public function getMessage()
-    {
-        return $this->_get(1);
-    }
-
-    /**
-     * Set <message> value.
-     *
-     * @param string $value
-     *
-     * @return \helloworld\HelloReply
-     */
-    public function setMessage($value)
-    {
-        return $this->_set(1, $value);
-    }
-  }
-}
-
-namespace helloworld {
-
-  class GreeterClient extends \Grpc\BaseStub
-  {
-      public function __construct($hostname, $opts)
-      {
-          parent::__construct($hostname, $opts);
-      }
-    /**
-     * @param helloworld\HelloRequest $input
-     */
-    public function SayHello(\helloworld\HelloRequest $argument, $metadata = array(), $options = array())
-    {
-        return $this->_simpleRequest('/helloworld.Greeter/SayHello', $argument, '\helloworld\HelloReply::deserialize', $metadata, $options);
-    }
-  }
-}

examples/php/helloworld_grpc_pb.php

@@ -0,0 +1,64 @@
+<?php
+// GENERATED CODE -- DO NOT EDIT!
+
+// Original file comments:
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+namespace Helloworld {
+
+  // The greeting service definition.
+  class GreeterClient extends \Grpc\BaseStub {
+
+    /**
+     * @param string $hostname hostname
+     * @param array $opts channel options
+     * @param Grpc\Channel $channel (optional) re-use channel object
+     */
+    public function __construct($hostname, $opts, $channel = null) {
+      parent::__construct($hostname, $opts, $channel);
+    }
+
+    /**
+     * Sends a greeting
+     * @param \Helloworld\HelloRequest $argument input argument
+     * @param array $metadata metadata
+     * @param array $options call options
+     */
+    public function SayHello(\Helloworld\HelloRequest $argument,
+      $metadata = [], $options = []) {
+      return $this->_simpleRequest('/helloworld.Greeter/SayHello',
+      $argument,
+      ['\Helloworld\HelloReply', 'decode'],
+      $metadata, $options);
+    }
+
+  }
+
+}

examples/php/route_guide/route_guide.pb.php

@@ -0,0 +1,209 @@
+<?php
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: route_guide.proto
+
+namespace Routeguide;
+
+use Google\Protobuf\Internal\DescriptorPool;
+use Google\Protobuf\Internal\GPBType;
+use Google\Protobuf\Internal\RepeatedField;
+use Google\Protobuf\Internal\GPBUtil;
+
+class Point extends \Google\Protobuf\Internal\Message
+{
+    private $latitude = 0;
+    private $longitude = 0;
+
+    public function getLatitude()
+    {
+        return $this->latitude;
+    }
+
+    public function setLatitude($var)
+    {
+        GPBUtil::checkInt32($var);
+        $this->latitude = $var;
+    }
+
+    public function getLongitude()
+    {
+        return $this->longitude;
+    }
+
+    public function setLongitude($var)
+    {
+        GPBUtil::checkInt32($var);
+        $this->longitude = $var;
+    }
+
+}
+
+class Rectangle extends \Google\Protobuf\Internal\Message
+{
+    private $lo = null;
+    private $hi = null;
+
+    public function getLo()
+    {
+        return $this->lo;
+    }
+
+    public function setLo(&$var)
+    {
+        GPBUtil::checkMessage($var, \Routeguide\Point::class);
+        $this->lo = $var;
+    }
+
+    public function getHi()
+    {
+        return $this->hi;
+    }
+
+    public function setHi(&$var)
+    {
+        GPBUtil::checkMessage($var, \Routeguide\Point::class);
+        $this->hi = $var;
+    }
+
+}
+
+class Feature extends \Google\Protobuf\Internal\Message
+{
+    private $name = '';
+    private $location = null;
+
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    public function setName($var)
+    {
+        GPBUtil::checkString($var, True);
+        $this->name = $var;
+    }
+
+    public function getLocation()
+    {
+        return $this->location;
+    }
+
+    public function setLocation(&$var)
+    {
+        GPBUtil::checkMessage($var, \Routeguide\Point::class);
+        $this->location = $var;
+    }
+
+}
+
+class RouteNote extends \Google\Protobuf\Internal\Message
+{
+    private $location = null;
+    private $message = '';
+
+    public function getLocation()
+    {
+        return $this->location;
+    }
+
+    public function setLocation(&$var)
+    {
+        GPBUtil::checkMessage($var, \Routeguide\Point::class);
+        $this->location = $var;
+    }
+
+    public function getMessage()
+    {
+        return $this->message;
+    }
+
+    public function setMessage($var)
+    {
+        GPBUtil::checkString($var, True);
+        $this->message = $var;
+    }
+
+}
+
+class RouteSummary extends \Google\Protobuf\Internal\Message
+{
+    private $point_count = 0;
+    private $feature_count = 0;
+    private $distance = 0;
+    private $elapsed_time = 0;
+
+    public function getPointCount()
+    {
+        return $this->point_count;
+    }
+
+    public function setPointCount($var)
+    {
+        GPBUtil::checkInt32($var);
+        $this->point_count = $var;
+    }
+
+    public function getFeatureCount()
+    {
+        return $this->feature_count;
+    }
+
+    public function setFeatureCount($var)
+    {
+        GPBUtil::checkInt32($var);
+        $this->feature_count = $var;
+    }
+
+    public function getDistance()
+    {
+        return $this->distance;
+    }
+
+    public function setDistance($var)
+    {
+        GPBUtil::checkInt32($var);
+        $this->distance = $var;
+    }
+
+    public function getElapsedTime()
+    {
+        return $this->elapsed_time;
+    }
+
+    public function setElapsedTime($var)
+    {
+        GPBUtil::checkInt32($var);
+        $this->elapsed_time = $var;
+    }
+
+}
+
+$pool = DescriptorPool::getGeneratedPool();
+
+$pool->internalAddGeneratedFile(hex2bin(
+    "0ac5050a11726f7574655f67756964652e70726f746f120a726f75746567" .
+    "75696465222c0a05506f696e7412100a086c617469747564651801200128" .
+    "0512110a096c6f6e67697475646518022001280522490a0952656374616e" .
+    "676c65121d0a026c6f18012001280b32112e726f75746567756964652e50" .
+    "6f696e74121d0a02686918022001280b32112e726f75746567756964652e" .
+    "506f696e74223c0a0746656174757265120c0a046e616d65180120012809" .
+    "12230a086c6f636174696f6e18022001280b32112e726f75746567756964" .
+    "652e506f696e7422410a09526f7574654e6f746512230a086c6f63617469" .
+    "6f6e18012001280b32112e726f75746567756964652e506f696e74120f0a" .
+    "076d65737361676518022001280922620a0c526f75746553756d6d617279" .
+    "12130a0b706f696e745f636f756e7418012001280512150a0d6665617475" .
+    "72655f636f756e7418022001280512100a0864697374616e636518032001" .
+    "280512140a0c656c61707365645f74696d651804200128053285020a0a52" .
+    "6f757465477569646512360a0a4765744665617475726512112e726f7574" .
+    "6567756964652e506f696e741a132e726f75746567756964652e46656174" .
+    "7572652200123e0a0c4c697374466561747572657312152e726f75746567" .
+    "756964652e52656374616e676c651a132e726f75746567756964652e4665" .
+    "617475726522003001123e0a0b5265636f7264526f75746512112e726f75" .
+    "746567756964652e506f696e741a182e726f75746567756964652e526f75" .
+    "746553756d6d61727922002801123f0a09526f7574654368617412152e72" .
+    "6f75746567756964652e526f7574654e6f74651a152e726f757465677569" .
+    "64652e526f7574654e6f746522002801300142360a1b696f2e677270632e" .
+    "6578616d706c65732e726f7574656775696465420f526f75746547756964" .
+    "6550726f746f5001a20203525447620670726f746f33"
+));
+

examples/php/route_guide/route_guide.php

@@ -1,789 +0,0 @@
-<?php
-// DO NOT EDIT! Generated by Protobuf-PHP protoc plugin 1.0
-// Source: route_guide.proto
-//   Date: 2015-09-24 21:21:51
-
-namespace routeguide {
-
-  class Point extends \DrSlump\Protobuf\Message
-  {
-      /**  @var int */
-    public $latitude = 0;
-
-    /**  @var int */
-    public $longitude = 0;
-
-    /** @var \Closure[] */
-    protected static $__extensions = array();
-
-      public static function descriptor()
-      {
-          $descriptor = new \DrSlump\Protobuf\Descriptor(__CLASS__, 'routeguide.Point');
-
-      // OPTIONAL INT32 latitude = 1
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 1;
-          $f->name = 'latitude';
-          $f->type = \DrSlump\Protobuf::TYPE_INT32;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->default = 0;
-          $descriptor->addField($f);
-
-      // OPTIONAL INT32 longitude = 2
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 2;
-          $f->name = 'longitude';
-          $f->type = \DrSlump\Protobuf::TYPE_INT32;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->default = 0;
-          $descriptor->addField($f);
-
-          foreach (self::$__extensions as $cb) {
-              $descriptor->addField($cb(), true);
-          }
-
-          return $descriptor;
-      }
-
-    /**
-     * Check if <latitude> has a value.
-     *
-     * @return bool
-     */
-    public function hasLatitude()
-    {
-        return $this->_has(1);
-    }
-
-    /**
-     * Clear <latitude> value.
-     *
-     * @return \routeguide\Point
-     */
-    public function clearLatitude()
-    {
-        return $this->_clear(1);
-    }
-
-    /**
-     * Get <latitude> value.
-     *
-     * @return int
-     */
-    public function getLatitude()
-    {
-        return $this->_get(1);
-    }
-
-    /**
-     * Set <latitude> value.
-     *
-     * @param int $value
-     *
-     * @return \routeguide\Point
-     */
-    public function setLatitude($value)
-    {
-        return $this->_set(1, $value);
-    }
-
-    /**
-     * Check if <longitude> has a value.
-     *
-     * @return bool
-     */
-    public function hasLongitude()
-    {
-        return $this->_has(2);
-    }
-
-    /**
-     * Clear <longitude> value.
-     *
-     * @return \routeguide\Point
-     */
-    public function clearLongitude()
-    {
-        return $this->_clear(2);
-    }
-
-    /**
-     * Get <longitude> value.
-     *
-     * @return int
-     */
-    public function getLongitude()
-    {
-        return $this->_get(2);
-    }
-
-    /**
-     * Set <longitude> value.
-     *
-     * @param int $value
-     *
-     * @return \routeguide\Point
-     */
-    public function setLongitude($value)
-    {
-        return $this->_set(2, $value);
-    }
-  }
-}
-
-namespace routeguide {
-
-  class Rectangle extends \DrSlump\Protobuf\Message
-  {
-      /**  @var \routeguide\Point */
-    public $lo = null;
-
-    /**  @var \routeguide\Point */
-    public $hi = null;
-
-    /** @var \Closure[] */
-    protected static $__extensions = array();
-
-      public static function descriptor()
-      {
-          $descriptor = new \DrSlump\Protobuf\Descriptor(__CLASS__, 'routeguide.Rectangle');
-
-      // OPTIONAL MESSAGE lo = 1
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 1;
-          $f->name = 'lo';
-          $f->type = \DrSlump\Protobuf::TYPE_MESSAGE;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->reference = '\routeguide\Point';
-          $descriptor->addField($f);
-
-      // OPTIONAL MESSAGE hi = 2
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 2;
-          $f->name = 'hi';
-          $f->type = \DrSlump\Protobuf::TYPE_MESSAGE;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->reference = '\routeguide\Point';
-          $descriptor->addField($f);
-
-          foreach (self::$__extensions as $cb) {
-              $descriptor->addField($cb(), true);
-          }
-
-          return $descriptor;
-      }
-
-    /**
-     * Check if <lo> has a value.
-     *
-     * @return bool
-     */
-    public function hasLo()
-    {
-        return $this->_has(1);
-    }
-
-    /**
-     * Clear <lo> value.
-     *
-     * @return \routeguide\Rectangle
-     */
-    public function clearLo()
-    {
-        return $this->_clear(1);
-    }
-
-    /**
-     * Get <lo> value.
-     *
-     * @return \routeguide\Point
-     */
-    public function getLo()
-    {
-        return $this->_get(1);
-    }
-
-    /**
-     * Set <lo> value.
-     *
-     * @param \routeguide\Point $value
-     *
-     * @return \routeguide\Rectangle
-     */
-    public function setLo(\routeguide\Point $value)
-    {
-        return $this->_set(1, $value);
-    }
-
-    /**
-     * Check if <hi> has a value.
-     *
-     * @return bool
-     */
-    public function hasHi()
-    {
-        return $this->_has(2);
-    }
-
-    /**
-     * Clear <hi> value.
-     *
-     * @return \routeguide\Rectangle
-     */
-    public function clearHi()
-    {
-        return $this->_clear(2);
-    }
-
-    /**
-     * Get <hi> value.
-     *
-     * @return \routeguide\Point
-     */
-    public function getHi()
-    {
-        return $this->_get(2);
-    }
-
-    /**
-     * Set <hi> value.
-     *
-     * @param \routeguide\Point $value
-     *
-     * @return \routeguide\Rectangle
-     */
-    public function setHi(\routeguide\Point $value)
-    {
-        return $this->_set(2, $value);
-    }
-  }
-}
-
-namespace routeguide {
-
-  class Feature extends \DrSlump\Protobuf\Message
-  {
-      /**  @var string */
-    public $name = null;
-
-    /**  @var \routeguide\Point */
-    public $location = null;
-
-    /** @var \Closure[] */
-    protected static $__extensions = array();
-
-      public static function descriptor()
-      {
-          $descriptor = new \DrSlump\Protobuf\Descriptor(__CLASS__, 'routeguide.Feature');
-
-      // OPTIONAL STRING name = 1
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 1;
-          $f->name = 'name';
-          $f->type = \DrSlump\Protobuf::TYPE_STRING;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $descriptor->addField($f);
-
-      // OPTIONAL MESSAGE location = 2
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 2;
-          $f->name = 'location';
-          $f->type = \DrSlump\Protobuf::TYPE_MESSAGE;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->reference = '\routeguide\Point';
-          $descriptor->addField($f);
-
-          foreach (self::$__extensions as $cb) {
-              $descriptor->addField($cb(), true);
-          }
-
-          return $descriptor;
-      }
-
-    /**
-     * Check if <name> has a value.
-     *
-     * @return bool
-     */
-    public function hasName()
-    {
-        return $this->_has(1);
-    }
-
-    /**
-     * Clear <name> value.
-     *
-     * @return \routeguide\Feature
-     */
-    public function clearName()
-    {
-        return $this->_clear(1);
-    }
-
-    /**
-     * Get <name> value.
-     *
-     * @return string
-     */
-    public function getName()
-    {
-        return $this->_get(1);
-    }
-
-    /**
-     * Set <name> value.
-     *
-     * @param string $value
-     *
-     * @return \routeguide\Feature
-     */
-    public function setName($value)
-    {
-        return $this->_set(1, $value);
-    }
-
-    /**
-     * Check if <location> has a value.
-     *
-     * @return bool
-     */
-    public function hasLocation()
-    {
-        return $this->_has(2);
-    }
-
-    /**
-     * Clear <location> value.
-     *
-     * @return \routeguide\Feature
-     */
-    public function clearLocation()
-    {
-        return $this->_clear(2);
-    }
-
-    /**
-     * Get <location> value.
-     *
-     * @return \routeguide\Point
-     */
-    public function getLocation()
-    {
-        return $this->_get(2);
-    }
-
-    /**
-     * Set <location> value.
-     *
-     * @param \routeguide\Point $value
-     *
-     * @return \routeguide\Feature
-     */
-    public function setLocation(\routeguide\Point $value)
-    {
-        return $this->_set(2, $value);
-    }
-  }
-}
-
-namespace routeguide {
-
-  class RouteNote extends \DrSlump\Protobuf\Message
-  {
-      /**  @var \routeguide\Point */
-    public $location = null;
-
-    /**  @var string */
-    public $message = null;
-
-    /** @var \Closure[] */
-    protected static $__extensions = array();
-
-      public static function descriptor()
-      {
-          $descriptor = new \DrSlump\Protobuf\Descriptor(__CLASS__, 'routeguide.RouteNote');
-
-      // OPTIONAL MESSAGE location = 1
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 1;
-          $f->name = 'location';
-          $f->type = \DrSlump\Protobuf::TYPE_MESSAGE;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->reference = '\routeguide\Point';
-          $descriptor->addField($f);
-
-      // OPTIONAL STRING message = 2
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 2;
-          $f->name = 'message';
-          $f->type = \DrSlump\Protobuf::TYPE_STRING;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $descriptor->addField($f);
-
-          foreach (self::$__extensions as $cb) {
-              $descriptor->addField($cb(), true);
-          }
-
-          return $descriptor;
-      }
-
-    /**
-     * Check if <location> has a value.
-     *
-     * @return bool
-     */
-    public function hasLocation()
-    {
-        return $this->_has(1);
-    }
-
-    /**
-     * Clear <location> value.
-     *
-     * @return \routeguide\RouteNote
-     */
-    public function clearLocation()
-    {
-        return $this->_clear(1);
-    }
-
-    /**
-     * Get <location> value.
-     *
-     * @return \routeguide\Point
-     */
-    public function getLocation()
-    {
-        return $this->_get(1);
-    }
-
-    /**
-     * Set <location> value.
-     *
-     * @param \routeguide\Point $value
-     *
-     * @return \routeguide\RouteNote
-     */
-    public function setLocation(\routeguide\Point $value)
-    {
-        return $this->_set(1, $value);
-    }
-
-    /**
-     * Check if <message> has a value.
-     *
-     * @return bool
-     */
-    public function hasMessage()
-    {
-        return $this->_has(2);
-    }
-
-    /**
-     * Clear <message> value.
-     *
-     * @return \routeguide\RouteNote
-     */
-    public function clearMessage()
-    {
-        return $this->_clear(2);
-    }
-
-    /**
-     * Get <message> value.
-     *
-     * @return string
-     */
-    public function getMessage()
-    {
-        return $this->_get(2);
-    }
-
-    /**
-     * Set <message> value.
-     *
-     * @param string $value
-     *
-     * @return \routeguide\RouteNote
-     */
-    public function setMessage($value)
-    {
-        return $this->_set(2, $value);
-    }
-  }
-}
-
-namespace routeguide {
-
-  class RouteSummary extends \DrSlump\Protobuf\Message
-  {
-      /**  @var int */
-    public $point_count = 0;
-
-    /**  @var int */
-    public $feature_count = 0;
-
-    /**  @var int */
-    public $distance = 0;
-
-    /**  @var int */
-    public $elapsed_time = 0;
-
-    /** @var \Closure[] */
-    protected static $__extensions = array();
-
-      public static function descriptor()
-      {
-          $descriptor = new \DrSlump\Protobuf\Descriptor(__CLASS__, 'routeguide.RouteSummary');
-
-      // OPTIONAL INT32 point_count = 1
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 1;
-          $f->name = 'point_count';
-          $f->type = \DrSlump\Protobuf::TYPE_INT32;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->default = 0;
-          $descriptor->addField($f);
-
-      // OPTIONAL INT32 feature_count = 2
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 2;
-          $f->name = 'feature_count';
-          $f->type = \DrSlump\Protobuf::TYPE_INT32;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->default = 0;
-          $descriptor->addField($f);
-
-      // OPTIONAL INT32 distance = 3
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 3;
-          $f->name = 'distance';
-          $f->type = \DrSlump\Protobuf::TYPE_INT32;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->default = 0;
-          $descriptor->addField($f);
-
-      // OPTIONAL INT32 elapsed_time = 4
-      $f = new \DrSlump\Protobuf\Field();
-          $f->number = 4;
-          $f->name = 'elapsed_time';
-          $f->type = \DrSlump\Protobuf::TYPE_INT32;
-          $f->rule = \DrSlump\Protobuf::RULE_OPTIONAL;
-          $f->default = 0;
-          $descriptor->addField($f);
-
-          foreach (self::$__extensions as $cb) {
-              $descriptor->addField($cb(), true);
-          }
-
-          return $descriptor;
-      }
-
-    /**
-     * Check if <point_count> has a value.
-     *
-     * @return bool
-     */
-    public function hasPointCount()
-    {
-        return $this->_has(1);
-    }
-
-    /**
-     * Clear <point_count> value.
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function clearPointCount()
-    {
-        return $this->_clear(1);
-    }
-
-    /**
-     * Get <point_count> value.
-     *
-     * @return int
-     */
-    public function getPointCount()
-    {
-        return $this->_get(1);
-    }
-
-    /**
-     * Set <point_count> value.
-     *
-     * @param int $value
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function setPointCount($value)
-    {
-        return $this->_set(1, $value);
-    }
-
-    /**
-     * Check if <feature_count> has a value.
-     *
-     * @return bool
-     */
-    public function hasFeatureCount()
-    {
-        return $this->_has(2);
-    }
-
-    /**
-     * Clear <feature_count> value.
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function clearFeatureCount()
-    {
-        return $this->_clear(2);
-    }
-
-    /**
-     * Get <feature_count> value.
-     *
-     * @return int
-     */
-    public function getFeatureCount()
-    {
-        return $this->_get(2);
-    }
-
-    /**
-     * Set <feature_count> value.
-     *
-     * @param int $value
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function setFeatureCount($value)
-    {
-        return $this->_set(2, $value);
-    }
-
-    /**
-     * Check if <distance> has a value.
-     *
-     * @return bool
-     */
-    public function hasDistance()
-    {
-        return $this->_has(3);
-    }
-
-    /**
-     * Clear <distance> value.
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function clearDistance()
-    {
-        return $this->_clear(3);
-    }
-
-    /**
-     * Get <distance> value.
-     *
-     * @return int
-     */
-    public function getDistance()
-    {
-        return $this->_get(3);
-    }
-
-    /**
-     * Set <distance> value.
-     *
-     * @param int $value
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function setDistance($value)
-    {
-        return $this->_set(3, $value);
-    }
-
-    /**
-     * Check if <elapsed_time> has a value.
-     *
-     * @return bool
-     */
-    public function hasElapsedTime()
-    {
-        return $this->_has(4);
-    }
-
-    /**
-     * Clear <elapsed_time> value.
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function clearElapsedTime()
-    {
-        return $this->_clear(4);
-    }
-
-    /**
-     * Get <elapsed_time> value.
-     *
-     * @return int
-     */
-    public function getElapsedTime()
-    {
-        return $this->_get(4);
-    }
-
-    /**
-     * Set <elapsed_time> value.
-     *
-     * @param int $value
-     *
-     * @return \routeguide\RouteSummary
-     */
-    public function setElapsedTime($value)
-    {
-        return $this->_set(4, $value);
-    }
-  }
-}
-
-namespace routeguide {
-
-  class RouteGuideClient extends \Grpc\BaseStub
-  {
-      public function __construct($hostname, $opts)
-      {
-          parent::__construct($hostname, $opts);
-      }
-    /**
-     * @param routeguide\Point $input
-     */
-    public function GetFeature(\routeguide\Point $argument, $metadata = array(), $options = array())
-    {
-        return $this->_simpleRequest('/routeguide.RouteGuide/GetFeature', $argument, '\routeguide\Feature::deserialize', $metadata, $options);
-    }
-    /**
-     * @param routeguide\Rectangle $input
-     */
-    public function ListFeatures($argument, $metadata = array(), $options = array())
-    {
-        return $this->_serverStreamRequest('/routeguide.RouteGuide/ListFeatures', $argument, '\routeguide\Feature::deserialize', $metadata, $options);
-    }
-    /**
-     * @param routeguide\Point $input
-     */
-    public function RecordRoute($metadata = array())
-    {
-        return $this->_clientStreamRequest('/routeguide.RouteGuide/RecordRoute', '\routeguide\RouteSummary::deserialize', $metadata);
-    }
-    /**
-     * @param routeguide\RouteNote $input
-     */
-    public function RouteChat($metadata = array())
-    {
-        return $this->_bidiRequest('/routeguide.RouteGuide/RouteChat', '\routeguide\RouteNote::deserialize', $metadata);
-    }
-  }
-}

examples/php/route_guide/route_guide.proto

@@ -1,120 +0,0 @@
-// Copyright 2015, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-syntax = "proto2";
-
-option java_package = "io.grpc.examples";
-
-package routeguide;
-
-// Interface exported by the server.
-service RouteGuide {
-  // A simple RPC.
-  //
-  // Obtains the feature at a given position.
-  rpc GetFeature(Point) returns (Feature) {}
-
-  // A server-to-client streaming RPC.
-  //
-  // Obtains the Features available within the given Rectangle.  Results are
-  // streamed rather than returned at once (e.g. in a response message with a
-  // repeated field), as the rectangle may cover a large area and contain a
-  // huge number of features.
-  rpc ListFeatures(Rectangle) returns (stream Feature) {}
-
-  // A client-to-server streaming RPC.
-  //
-  // Accepts a stream of Points on a route being traversed, returning a
-  // RouteSummary when traversal is completed.
-  rpc RecordRoute(stream Point) returns (RouteSummary) {}
-
-  // A Bidirectional streaming RPC.
-  //
-  // Accepts a stream of RouteNotes sent while a route is being traversed,
-  // while receiving other RouteNotes (e.g. from other users).
-  rpc RouteChat(stream RouteNote) returns (stream RouteNote) {}
-}
-
-// Points are represented as latitude-longitude pairs in the E7 representation
-// (degrees multiplied by 10**7 and rounded to the nearest integer).
-// Latitudes should be in the range +/- 90 degrees and longitude should be in
-// the range +/- 180 degrees (inclusive).
-message Point {
-  optional int32 latitude = 1 [default = 0];
-  optional int32 longitude = 2 [default = 0];
-}
-
-// A latitude-longitude rectangle, represented as two diagonally opposite
-// points "lo" and "hi".
-message Rectangle {
-  // One corner of the rectangle.
-  optional Point lo = 1;
-
-  // The other corner of the rectangle.
-  optional Point hi = 2;
-}
-
-// A feature names something at a given point.
-//
-// If a feature could not be named, the name is empty.
-message Feature {
-  // The name of the feature.
-  optional string name = 1;
-
-  // The point where the feature is detected.
-  optional Point location = 2;
-}
-
-// A RouteNote is a message sent while at a given point.
-message RouteNote {
-  // The location from which the message is sent.
-  optional Point location = 1;
-
-  // The message to be sent.
-  optional string message = 2;
-}
-
-// A RouteSummary is received in response to a RecordRoute rpc.
-//
-// It contains the number of individual points received, the number of
-// detected features, and the total distance covered as the cumulative sum of
-// the distance between each point.
-message RouteSummary {
-  // The number of points received.
-  optional int32 point_count = 1 [default = 0];
-
-  // The number of known features passed while traversing the route.
-  optional int32 feature_count = 2 [default = 0];
-
-  // The distance covered in metres.
-  optional int32 distance = 3 [default = 0];
-
-  // The duration of the traversal in seconds.
-  optional int32 elapsed_time = 4 [default = 0];
-}

examples/php/route_guide/route_guide_client.php

@@ -33,11 +33,15 @@
  */
 
 require dirname(__FILE__).'/../vendor/autoload.php';
-require dirname(__FILE__).'/route_guide.php';
+
+// The following includes are needed when using protobuf 3.1.0
+// and will suppress warnings when using protobuf 3.2.0+
+@include_once dirname(__FILE__).'/route_guide.pb.php';
+@include_once dirname(__FILE__).'/route_guide_grpc_pb.php';
 
 define('COORD_FACTOR', 1e7);
 
-$client = new routeguide\RouteGuideClient('localhost:50051', [
+$client = new Routeguide\RouteGuideClient('localhost:50051', [
     'credentials' => Grpc\ChannelCredentials::createInsecure(),
 ]);
 
@@ -63,7 +67,7 @@ function runGetFeature()
     echo "Running GetFeature...\n";
     global $client;
 
-    $point = new routeguide\Point();
+    $point = new Routeguide\Point();
     $points = array(
         array(409146138, -746188906),
         array(0, 0),
@@ -88,15 +92,15 @@ function runListFeatures()
     echo "Running ListFeatures...\n";
     global $client;
 
-    $lo_point = new routeguide\Point();
-    $hi_point = new routeguide\Point();
+    $lo_point = new Routeguide\Point();
+    $hi_point = new Routeguide\Point();
 
     $lo_point->setLatitude(400000000);
     $lo_point->setLongitude(-750000000);
     $hi_point->setLatitude(420000000);
     $hi_point->setLongitude(-730000000);
 
-    $rectangle = new routeguide\Rectangle();
+    $rectangle = new Routeguide\Rectangle();
     $rectangle->setLo($lo_point);
     $rectangle->setHi($hi_point);
 
@@ -126,7 +130,7 @@ function runRecordRoute()
     $num_points_in_db = count($db);
     $num_points = 10;
     for ($i = 0; $i < $num_points; ++$i) {
-        $point = new routeguide\Point();
+        $point = new Routeguide\Point();
         $index = rand(0, $num_points_in_db - 1);
         $lat = $db[$index]['location']['latitude'];
         $long = $db[$index]['location']['longitude'];
@@ -169,11 +173,11 @@ function runRouteChat()
     );
 
     foreach ($notes as $n) {
-        $point = new routeguide\Point();
+        $point = new Routeguide\Point();
         $point->setLatitude($lat = $n[0]);
         $point->setLongitude($long = $n[1]);
 
-        $route_note = new routeguide\RouteNote();
+        $route_note = new Routeguide\RouteNote();
         $route_note->setLocation($point);
         $route_note->setMessage($message = $n[2]);
 

examples/php/route_guide/route_guide_grpc_pb.php

@@ -0,0 +1,116 @@
+<?php
+// GENERATED CODE -- DO NOT EDIT!
+
+// Original file comments:
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+namespace Routeguide {
+
+  // Interface exported by the server.
+  class RouteGuideClient extends \Grpc\BaseStub {
+
+    /**
+     * @param string $hostname hostname
+     * @param array $opts channel options
+     * @param Grpc\Channel $channel (optional) re-use channel object
+     */
+    public function __construct($hostname, $opts, $channel = null) {
+      parent::__construct($hostname, $opts, $channel);
+    }
+
+    /**
+     * A simple RPC.
+     *
+     * Obtains the feature at a given position.
+     *
+     * A feature with an empty name is returned if there's no feature at the given
+     * position.
+     * @param \Routeguide\Point $argument input argument
+     * @param array $metadata metadata
+     * @param array $options call options
+     */
+    public function GetFeature(\Routeguide\Point $argument,
+      $metadata = [], $options = []) {
+      return $this->_simpleRequest('/routeguide.RouteGuide/GetFeature',
+      $argument,
+      ['\Routeguide\Feature', 'decode'],
+      $metadata, $options);
+    }
+
+    /**
+     * A server-to-client streaming RPC.
+     *
+     * Obtains the Features available within the given Rectangle.  Results are
+     * streamed rather than returned at once (e.g. in a response message with a
+     * repeated field), as the rectangle may cover a large area and contain a
+     * huge number of features.
+     * @param \Routeguide\Rectangle $argument input argument
+     * @param array $metadata metadata
+     * @param array $options call options
+     */
+    public function ListFeatures(\Routeguide\Rectangle $argument,
+      $metadata = [], $options = []) {
+      return $this->_serverStreamRequest('/routeguide.RouteGuide/ListFeatures',
+      $argument,
+      ['\Routeguide\Feature', 'decode'],
+      $metadata, $options);
+    }
+
+    /**
+     * A client-to-server streaming RPC.
+     *
+     * Accepts a stream of Points on a route being traversed, returning a
+     * RouteSummary when traversal is completed.
+     * @param array $metadata metadata
+     * @param array $options call options
+     */
+    public function RecordRoute($metadata = [], $options = []) {
+      return $this->_clientStreamRequest('/routeguide.RouteGuide/RecordRoute',
+      ['\Routeguide\RouteSummary','decode'],
+      $metadata, $options);
+    }
+
+    /**
+     * A Bidirectional streaming RPC.
+     *
+     * Accepts a stream of RouteNotes sent while a route is being traversed,
+     * while receiving other RouteNotes (e.g. from other users).
+     * @param array $metadata metadata
+     * @param array $options call options
+     */
+    public function RouteChat($metadata = [], $options = []) {
+      return $this->_bidiRequest('/routeguide.RouteGuide/RouteChat',
+      ['\Routeguide\RouteNote','decode'],
+      $metadata, $options);
+    }
+
+  }
+
+}

gRPC-Core.podspec

@@ -1,8 +1,10 @@
-# GRPC CocoaPods podspec
-# This file has been automatically generated from a template file. Please make modifications to
-# `templates/gRPC-Core.podspec.template` instead. This file can be regenerated from the template by
-# running `tools/buildgen/generate_projects.sh`.
+# This file has been automatically generated from a template file.
+# Please make modifications to `templates/gRPC-Core.podspec.template`
+# instead. This file can be regenerated from the template by running
+# `tools/buildgen/generate_projects.sh`.
 
+# gRPC Core CocoaPods podspec
+#
 # Copyright 2015, Google Inc.
 # All rights reserved.
 #
@@ -35,7 +37,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-Core'
-  version = '1.0.2'
+  version = '1.2.0-dev'
   s.version  = version
   s.summary  = 'Core cross-platform gRPC library, written in C'
   s.homepage = 'http://www.grpc.io'
@@ -44,9 +46,7 @@ Pod::Spec.new do |s|
 
   s.source = {
     :git => 'https://github.com/grpc/grpc.git',
-    # TODO(mxyan): Change back to "v#{version}" for next release
-    #:tag => "v#{version}",
-    :tag => "objective-c-v#{version}",
+    :tag => "v#{version}",
     # TODO(jcanizales): Depend explicitly on the nanopb pod, and disable submodules.
     :submodules => true,
   }
@@ -191,7 +191,7 @@ Pod::Spec.new do |s|
     ss.header_mappings_dir = '.'
     ss.libraries = 'z'
     ss.dependency "#{s.name}/Interface", version
-    ss.dependency 'BoringSSL', '~> 7.0'
+    ss.dependency 'BoringSSL', '~> 8.0'
 
     # To save you from scrolling, this is the last part of the podspec.
     ss.source_files = 'src/core/lib/profiling/timers.h',
@@ -342,6 +342,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/surface/lame_client.h',
                       'src/core/lib/surface/server.h',
                       'src/core/lib/surface/validate_metadata.h',
+                      'src/core/lib/transport/bdp_estimator.h',
                       'src/core/lib/transport/byte_stream.h',
                       'src/core/lib/transport/connectivity_state.h',
                       'src/core/lib/transport/error_utils.h',
@@ -387,6 +388,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/security/credentials/plugin/plugin_credentials.h',
                       'src/core/lib/security/credentials/ssl/ssl_credentials.h',
                       'src/core/lib/security/transport/auth_filters.h',
+                      'src/core/lib/security/transport/lb_targets_info.h',
                       'src/core/lib/security/transport/secure_endpoint.h',
                       'src/core/lib/security/transport/security_connector.h',
                       'src/core/lib/security/transport/security_handshaker.h',
@@ -419,6 +421,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/client_channel/uri_parser.h',
                       'src/core/ext/transport/chttp2/client/chttp2_connector.h',
                       'src/core/ext/lb_policy/grpclb/grpclb.h',
+                      'src/core/ext/lb_policy/grpclb/grpclb_channel.h',
                       'src/core/ext/lb_policy/grpclb/load_balancer_api.h',
                       'src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h',
                       'third_party/nanopb/pb.h',
@@ -438,6 +441,11 @@ Pod::Spec.new do |s|
                       'src/core/ext/census/resource.h',
                       'src/core/ext/census/rpc_metric_id.h',
                       'src/core/ext/census/trace_context.h',
+                      'src/core/ext/census/trace_label.h',
+                      'src/core/ext/census/trace_propagation.h',
+                      'src/core/ext/census/trace_status.h',
+                      'src/core/ext/census/trace_string.h',
+                      'src/core/ext/census/tracing.h',
                       'src/core/lib/surface/init.c',
                       'src/core/lib/channel/channel_args.c',
                       'src/core/lib/channel/channel_stack.c',
@@ -544,6 +552,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/surface/server.c',
                       'src/core/lib/surface/validate_metadata.c',
                       'src/core/lib/surface/version.c',
+                      'src/core/lib/transport/bdp_estimator.c',
                       'src/core/lib/transport/byte_stream.c',
                       'src/core/lib/transport/connectivity_state.c',
                       'src/core/lib/transport/error_utils.c',
@@ -594,6 +603,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/security/credentials/plugin/plugin_credentials.c',
                       'src/core/lib/security/credentials/ssl/ssl_credentials.c',
                       'src/core/lib/security/transport/client_auth_filter.c',
+                      'src/core/lib/security/transport/lb_targets_info.c',
                       'src/core/lib/security/transport/secure_endpoint.c',
                       'src/core/lib/security/transport/security_connector.c',
                       'src/core/lib/security/transport/security_handshaker.c',
@@ -634,6 +644,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/transport/chttp2/client/insecure/channel_create.c',
                       'src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c',
                       'src/core/ext/lb_policy/grpclb/grpclb.c',
+                      'src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c',
                       'src/core/ext/lb_policy/grpclb/load_balancer_api.c',
                       'src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c',
                       'third_party/nanopb/pb_common.c',
@@ -765,6 +776,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/surface/lame_client.h',
                               'src/core/lib/surface/server.h',
                               'src/core/lib/surface/validate_metadata.h',
+                              'src/core/lib/transport/bdp_estimator.h',
                               'src/core/lib/transport/byte_stream.h',
                               'src/core/lib/transport/connectivity_state.h',
                               'src/core/lib/transport/error_utils.h',
@@ -810,6 +822,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/security/credentials/plugin/plugin_credentials.h',
                               'src/core/lib/security/credentials/ssl/ssl_credentials.h',
                               'src/core/lib/security/transport/auth_filters.h',
+                              'src/core/lib/security/transport/lb_targets_info.h',
                               'src/core/lib/security/transport/secure_endpoint.h',
                               'src/core/lib/security/transport/security_connector.h',
                               'src/core/lib/security/transport/security_handshaker.h',
@@ -842,6 +855,7 @@ Pod::Spec.new do |s|
                               'src/core/ext/client_channel/uri_parser.h',
                               'src/core/ext/transport/chttp2/client/chttp2_connector.h',
                               'src/core/ext/lb_policy/grpclb/grpclb.h',
+                              'src/core/ext/lb_policy/grpclb/grpclb_channel.h',
                               'src/core/ext/lb_policy/grpclb/load_balancer_api.h',
                               'src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h',
                               'third_party/nanopb/pb.h',
@@ -860,7 +874,12 @@ Pod::Spec.new do |s|
                               'src/core/ext/census/mlog.h',
                               'src/core/ext/census/resource.h',
                               'src/core/ext/census/rpc_metric_id.h',
-                              'src/core/ext/census/trace_context.h'
+                              'src/core/ext/census/trace_context.h',
+                              'src/core/ext/census/trace_label.h',
+                              'src/core/ext/census/trace_propagation.h',
+                              'src/core/ext/census/trace_status.h',
+                              'src/core/ext/census/trace_string.h',
+                              'src/core/ext/census/tracing.h'
   end
 
   s.subspec 'Cronet-Interface' do |ss|
@@ -871,13 +890,22 @@ Pod::Spec.new do |s|
 
   s.subspec 'Cronet-Implementation' do |ss|
     ss.header_mappings_dir = '.'
+
+    ss.dependency "#{s.name}/Interface", version
+    ss.dependency "#{s.name}/Implementation", version
+    ss.dependency "#{s.name}/Cronet-Interface", version
+
     ss.source_files = 'src/core/ext/transport/cronet/client/secure/cronet_channel_create.c',
-                      'src/core/ext/transport/cronet/transport/cronet_transport.c'
+                      'src/core/ext/transport/cronet/transport/cronet_transport.c',
+                      'third_party/objective_c/Cronet/bidirectional_stream_c.h'
   end
 
   s.subspec 'Tests' do |ss|
     ss.header_mappings_dir = '.'
 
+    ss.dependency "#{s.name}/Interface", version
+    ss.dependency "#{s.name}/Implementation", version
+
     ss.source_files = 'test/core/end2end/cq_verifier.{c,h}',
                       'test/core/end2end/end2end_tests.{c,h}',
                       'test/core/end2end/end2end_test_utils.c',
@@ -888,7 +916,5 @@ Pod::Spec.new do |s|
                       'test/core/util/port.h',
                       'test/core/util/port_posix.c',
                       'test/core/util/port_server_client.{c,h}'
-
-    ss.dependency 'CronetFramework'
   end
 end

gRPC-ProtoRPC.podspec

@@ -1,3 +1,9 @@
+# This file has been automatically generated from a template file.
+# Please make modifications to
+# `templates/gRPC-ProtoRPC.podspec.template` instead. This file can be
+# regenerated from the template by running
+# `tools/buildgen/generate_projects.sh`.
+
 # Copyright 2015, Google Inc.
 # All rights reserved.
 #
@@ -30,7 +36,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-ProtoRPC'
-  version = '1.0.2'
+  version = '1.2.0-dev'
   s.version  = version
   s.summary  = 'RPC library for Protocol Buffers, based on gRPC'
   s.homepage = 'http://www.grpc.io'
@@ -39,7 +45,7 @@ Pod::Spec.new do |s|
 
   s.source = {
     :git => 'https://github.com/grpc/grpc.git',
-    :tag => "objective-c-v#{version}",
+    :tag => "v#{version}",
   }
 
   s.ios.deployment_target = '7.1'

gRPC-RxLibrary.podspec

@@ -1,3 +1,9 @@
+# This file has been automatically generated from a template file.
+# Please make modifications to
+# `templates/gRPC-RxLibrary.podspec.template` instead. This file can be
+# regenerated from the template by running
+# `tools/buildgen/generate_projects.sh`.
+
 # Copyright 2015, Google Inc.
 # All rights reserved.
 #
@@ -30,7 +36,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-RxLibrary'
-  version = '1.0.2'
+  version = '1.2.0-dev'
   s.version  = version
   s.summary  = 'Reactive Extensions library for iOS/OSX.'
   s.homepage = 'http://www.grpc.io'
@@ -39,7 +45,7 @@ Pod::Spec.new do |s|
 
   s.source = {
     :git => 'https://github.com/grpc/grpc.git',
-    :tag => "objective-c-v#{version}",
+    :tag => "v#{version}",
   }
 
   s.ios.deployment_target = '7.1'

gRPC.podspec

@@ -1,3 +1,8 @@
+# This file has been automatically generated from a template file.
+# Please make modifications to `templates/gRPC.podspec.template`
+# instead. This file can be regenerated from the template by running
+# `tools/buildgen/generate_projects.sh`.
+
 # Copyright 2015, Google Inc.
 # All rights reserved.
 #
@@ -30,7 +35,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC'
-  version = '1.0.2'
+  version = '1.2.0-dev'
   s.version  = version
   s.summary  = 'gRPC client library for iOS/OSX'
   s.homepage = 'http://www.grpc.io'
@@ -39,7 +44,7 @@ Pod::Spec.new do |s|
 
   s.source = {
     :git => 'https://github.com/grpc/grpc.git',
-    :tag => "objective-c-v#{version}",
+    :tag => "v#{version}",
   }
 
   s.ios.deployment_target = '7.1'

grpc.gemspec

@@ -259,6 +259,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/surface/lame_client.h )
   s.files += %w( src/core/lib/surface/server.h )
   s.files += %w( src/core/lib/surface/validate_metadata.h )
+  s.files += %w( src/core/lib/transport/bdp_estimator.h )
   s.files += %w( src/core/lib/transport/byte_stream.h )
   s.files += %w( src/core/lib/transport/connectivity_state.h )
   s.files += %w( src/core/lib/transport/error_utils.h )
@@ -304,6 +305,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/security/credentials/plugin/plugin_credentials.h )
   s.files += %w( src/core/lib/security/credentials/ssl/ssl_credentials.h )
   s.files += %w( src/core/lib/security/transport/auth_filters.h )
+  s.files += %w( src/core/lib/security/transport/lb_targets_info.h )
   s.files += %w( src/core/lib/security/transport/secure_endpoint.h )
   s.files += %w( src/core/lib/security/transport/security_connector.h )
   s.files += %w( src/core/lib/security/transport/security_handshaker.h )
@@ -336,6 +338,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/client_channel/uri_parser.h )
   s.files += %w( src/core/ext/transport/chttp2/client/chttp2_connector.h )
   s.files += %w( src/core/ext/lb_policy/grpclb/grpclb.h )
+  s.files += %w( src/core/ext/lb_policy/grpclb/grpclb_channel.h )
   s.files += %w( src/core/ext/lb_policy/grpclb/load_balancer_api.h )
   s.files += %w( src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h )
   s.files += %w( third_party/nanopb/pb.h )
@@ -355,6 +358,11 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/census/resource.h )
   s.files += %w( src/core/ext/census/rpc_metric_id.h )
   s.files += %w( src/core/ext/census/trace_context.h )
+  s.files += %w( src/core/ext/census/trace_label.h )
+  s.files += %w( src/core/ext/census/trace_propagation.h )
+  s.files += %w( src/core/ext/census/trace_status.h )
+  s.files += %w( src/core/ext/census/trace_string.h )
+  s.files += %w( src/core/ext/census/tracing.h )
   s.files += %w( src/core/lib/surface/init.c )
   s.files += %w( src/core/lib/channel/channel_args.c )
   s.files += %w( src/core/lib/channel/channel_stack.c )
@@ -461,6 +469,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/surface/server.c )
   s.files += %w( src/core/lib/surface/validate_metadata.c )
   s.files += %w( src/core/lib/surface/version.c )
+  s.files += %w( src/core/lib/transport/bdp_estimator.c )
   s.files += %w( src/core/lib/transport/byte_stream.c )
   s.files += %w( src/core/lib/transport/connectivity_state.c )
   s.files += %w( src/core/lib/transport/error_utils.c )
@@ -511,6 +520,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/security/credentials/plugin/plugin_credentials.c )
   s.files += %w( src/core/lib/security/credentials/ssl/ssl_credentials.c )
   s.files += %w( src/core/lib/security/transport/client_auth_filter.c )
+  s.files += %w( src/core/lib/security/transport/lb_targets_info.c )
   s.files += %w( src/core/lib/security/transport/secure_endpoint.c )
   s.files += %w( src/core/lib/security/transport/security_connector.c )
   s.files += %w( src/core/lib/security/transport/security_handshaker.c )
@@ -551,6 +561,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/transport/chttp2/client/insecure/channel_create.c )
   s.files += %w( src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c )
   s.files += %w( src/core/ext/lb_policy/grpclb/grpclb.c )
+  s.files += %w( src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c )
   s.files += %w( src/core/ext/lb_policy/grpclb/load_balancer_api.c )
   s.files += %w( src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c )
   s.files += %w( third_party/nanopb/pb_common.c )

include/grpc++/impl/codegen/proto_utils.h

@@ -50,6 +50,8 @@ extern CoreCodegenInterface* g_core_codegen_interface;
 
 namespace internal {
 
+class GrpcBufferWriterPeer;
+
 const int kGrpcBufferWriterMaxBufferLength = 8192;
 
 class GrpcBufferWriter final
@@ -91,13 +93,18 @@ class GrpcBufferWriter final
           &slice_, GRPC_SLICE_LENGTH(slice_) - count);
       g_core_codegen_interface->grpc_slice_buffer_add(slice_buffer_, slice_);
     }
-    have_backup_ = true;
+    // It's dangerous to keep an inlined grpc_slice as the backup slice, since
+    // on a following Next() call, a reference will be returned to this slice
+    // via GRPC_SLICE_START_PTR, which will not be an adddress held by
+    // slice_buffer_.
+    have_backup_ = backup_slice_.refcount != NULL;
     byte_count_ -= count;
   }
 
   grpc::protobuf::int64 ByteCount() const override { return byte_count_; }
 
  private:
+  friend class GrpcBufferWriterPeer;
   const int block_size_;
   int64_t byte_count_;
   grpc_slice_buffer* slice_buffer_;

include/grpc++/server.h

@@ -88,6 +88,8 @@ class Server final : public ServerInterface, private GrpcLibraryCodegen {
     virtual void PreSynchronousRequest(ServerContext* context) = 0;
     /// Called after application callback for each synchronous server request
     virtual void PostSynchronousRequest(ServerContext* context) = 0;
+    /// Called before server is started.
+    virtual void PreServerStart(Server* server) {}
   };
   /// Set the global callback object. Can only be called once. Does not take
   /// ownership of callbacks, and expects the pointed to object to be alive

include/grpc/census.h

@@ -156,7 +156,7 @@ CENSUSAPI void census_context_destroy(census_context *context);
 CENSUSAPI const census_context_status *census_context_get_status(
     const census_context *context);
 
-/* Structure used for iterating over the tegs in a context. API clients should
+/* Structure used for iterating over the tags in a context. API clients should
    not use or reference internal fields - neither their contents or
    presence/absence are guaranteed. */
 typedef struct {
@@ -180,7 +180,7 @@ CENSUSAPI int census_context_next_tag(census_context_iterator *iterator,
 CENSUSAPI int census_context_get_tag(const census_context *context,
                                      const char *key, census_tag *tag);
 
-/* Tag set encode/decode functionality. These functionas are intended
+/* Tag set encode/decode functionality. These functions are intended
    for use by RPC systems only, for purposes of transmitting/receiving contexts.
    */
 
@@ -205,14 +205,14 @@ enum census_trace_mask_values {
 };
 
 /** Get the current trace mask associated with this context. The value returned
-    will be the logical or of census_trace_mask_values values. */
+    will be the logical OR of census_trace_mask_values values. */
 CENSUSAPI int census_trace_mask(const census_context *context);
 
 /** Set the trace mask associated with a context. */
 CENSUSAPI void census_set_trace_mask(int trace_mask);
 
 /* The concept of "operation" is a fundamental concept for Census. In an RPC
-   system, and operation typcially represents a single RPC, or a significant
+   system, an operation typically represents a single RPC, or a significant
    sub-part thereof (e.g. a single logical "read" RPC to a distributed storage
    system might do several other actions in parallel, from looking up metadata
    indices to making requests of other services - each of these could be a
@@ -362,7 +362,7 @@ CENSUSAPI census_context *census_start_server_rpc_op(
 
    @param context The base context. Can be NULL.
    @param family Family name to associate with the trace
-   @param name Name within family to associated with traces/stats
+   @param name Name within family to associate with traces/stats
    @param trace_mask An OR of census_trace_mask_values values. Only used if
                      context is NULL.
 
@@ -454,7 +454,7 @@ CENSUSAPI void census_trace_scan_end();
    protobuf, `resource_pb_size` being the size of the buffer. Returns a -ve
    value on error, or a positive (>= 0) resource id (for use in
    census_delete_resource() and census_record_values()). In order to be valid, a
-   resource must have a name, and at least one numerator in it's unit type. The
+   resource must have a name, and at least one numerator in its unit type. The
    resource name must be unique, and an error will be returned if it is not. */
 CENSUSAPI int32_t census_define_resource(const uint8_t *resource_pb,
                                          size_t resource_pb_size);
@@ -462,7 +462,7 @@ CENSUSAPI int32_t census_define_resource(const uint8_t *resource_pb,
 /* Delete a resource created by census_define_resource(). */
 CENSUSAPI void census_delete_resource(int32_t resource_id);
 
-/* Determine the id of a resource, given it's name. returns -1 if the resource
+/* Determine the id of a resource, given its name. returns -1 if the resource
    does not exist. */
 CENSUSAPI int32_t census_resource_id(const char *name);
 

include/grpc/impl/codegen/grpc_types.h

@@ -179,6 +179,17 @@ typedef struct {
     Larger values give lower CPU usage for large messages, but more head of line
     blocking for small messages. */
 #define GRPC_ARG_HTTP2_MAX_FRAME_SIZE "grpc.http2.max_frame_size"
+/** Should BDP probing be performed? */
+#define GRPC_ARG_HTTP2_BDP_PROBE "grpc.http2.bdp_probe"
+/** Minimum time (in milliseconds) between successive ping frames being sent */
+#define GRPC_ARG_HTTP2_MIN_TIME_BETWEEN_PINGS_MS \
+  "grpc.http2.min_time_between_pings_ms"
+/** How many pings can we send before needing to send a data frame or header
+    frame?
+    (0 indicates that an infinite number of pings can be sent without sending
+     a data frame or header frame) */
+#define GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA \
+  "grpc.http2.max_pings_without_data"
 /** How much data are we willing to queue up per stream if
     GRPC_WRITE_BUFFER_HINT is set? This is an upper bound */
 #define GRPC_ARG_HTTP2_WRITE_BUFFER_SIZE "grpc.http2.write_buffer_size"
@@ -211,6 +222,8 @@ typedef struct {
 /** If non-zero, a pointer to a buffer pool (use grpc_resource_quota_arg_vtable
    to fetch an appropriate pointer arg vtable) */
 #define GRPC_ARG_RESOURCE_QUOTA "grpc.resource_quota"
+/** If non-zero, expand wildcard addresses to a list of local addresses. */
+#define GRPC_ARG_EXPAND_WILDCARD_ADDRS "grpc.expand_wildcard_addrs"
 /** Service config data in JSON form. Not intended for use outside of tests. */
 #define GRPC_ARG_SERVICE_CONFIG "grpc.service_config"
 /** LB policy name. */

package.xml

@@ -268,6 +268,7 @@
     <file baseinstalldir="/" name="src/core/lib/surface/lame_client.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/server.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/validate_metadata.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/bdp_estimator.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/byte_stream.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/connectivity_state.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/error_utils.h" role="src" />
@@ -313,6 +314,7 @@
     <file baseinstalldir="/" name="src/core/lib/security/credentials/plugin/plugin_credentials.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/credentials/ssl/ssl_credentials.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/auth_filters.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/security/transport/lb_targets_info.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/secure_endpoint.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/security_connector.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/security_handshaker.h" role="src" />
@@ -345,6 +347,7 @@
     <file baseinstalldir="/" name="src/core/ext/client_channel/uri_parser.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/client/chttp2_connector.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/grpclb.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/grpclb_channel.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/load_balancer_api.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h" role="src" />
     <file baseinstalldir="/" name="third_party/nanopb/pb.h" role="src" />
@@ -364,6 +367,11 @@
     <file baseinstalldir="/" name="src/core/ext/census/resource.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/census/rpc_metric_id.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/census/trace_context.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/census/trace_label.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/census/trace_propagation.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/census/trace_status.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/census/trace_string.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/census/tracing.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/init.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/channel/channel_args.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/channel/channel_stack.c" role="src" />
@@ -470,6 +478,7 @@
     <file baseinstalldir="/" name="src/core/lib/surface/server.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/validate_metadata.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/version.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/bdp_estimator.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/byte_stream.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/connectivity_state.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/error_utils.c" role="src" />
@@ -520,6 +529,7 @@
     <file baseinstalldir="/" name="src/core/lib/security/credentials/plugin/plugin_credentials.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/credentials/ssl/ssl_credentials.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/client_auth_filter.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/security/transport/lb_targets_info.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/secure_endpoint.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/security_connector.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/security/transport/security_handshaker.c" role="src" />
@@ -560,6 +570,7 @@
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/client/insecure/channel_create.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/grpclb.c" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/load_balancer_api.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c" role="src" />
     <file baseinstalldir="/" name="third_party/nanopb/pb_common.c" role="src" />

src/core/ext/census/gen/trace_context.pb.c

@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2016, Google Inc.
+ * Copyright 2017, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,51 +31,24 @@
  *
  */
 /* Automatically generated nanopb constant definitions */
-/* Generated by nanopb-0.3.5-dev */
+/* Generated by nanopb-0.3.7-dev at Fri Jan 20 16:14:22 2017. */
 
 #include "src/core/ext/census/gen/trace_context.pb.h"
 
+/* @@protoc_insertion_point(includes) */
 #if PB_PROTO_HEADER_VERSION != 30
 #error Regenerate this file with the current version of nanopb generator.
 #endif
 
 
 
-const pb_field_t google_trace_TraceId_fields[3] = {
-    PB_FIELD(  1, FIXED64 , OPTIONAL, STATIC  , FIRST, google_trace_TraceId, hi, hi, 0),
-    PB_FIELD(  2, FIXED64 , OPTIONAL, STATIC  , OTHER, google_trace_TraceId, lo, hi, 0),
+const pb_field_t google_trace_TraceContext_fields[5] = {
+    PB_FIELD(  1, FIXED64 , OPTIONAL, STATIC  , FIRST, google_trace_TraceContext, trace_id_hi, trace_id_hi, 0),
+    PB_FIELD(  2, FIXED64 , OPTIONAL, STATIC  , OTHER, google_trace_TraceContext, trace_id_lo, trace_id_hi, 0),
+    PB_FIELD(  3, FIXED64 , OPTIONAL, STATIC  , OTHER, google_trace_TraceContext, span_id, trace_id_lo, 0),
+    PB_FIELD(  4, FIXED32 , OPTIONAL, STATIC  , OTHER, google_trace_TraceContext, span_options, span_id, 0),
     PB_LAST_FIELD
 };
 
-const pb_field_t google_trace_TraceContext_fields[4] = {
-    PB_FIELD(  1, MESSAGE , OPTIONAL, STATIC  , FIRST, google_trace_TraceContext, trace_id, trace_id, &google_trace_TraceId_fields),
-    PB_FIELD(  2, FIXED64 , OPTIONAL, STATIC  , OTHER, google_trace_TraceContext, span_id, trace_id, 0),
-    PB_FIELD(  3, BOOL    , OPTIONAL, STATIC  , OTHER, google_trace_TraceContext, is_sampled, span_id, 0),
-    PB_LAST_FIELD
-};
-
-
-/* Check that field information fits in pb_field_t */
-#if !defined(PB_FIELD_32BIT)
-/* If you get an error here, it means that you need to define PB_FIELD_32BIT
- * compile-time option. You can do that in pb.h or on compiler command line.
- * 
- * The reason you need to do this is that some of your messages contain tag
- * numbers or field sizes that are larger than what can fit in 8 or 16 bit
- * field descriptors.
- */
-PB_STATIC_ASSERT((pb_membersize(google_trace_TraceContext, trace_id) < 65536), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_google_trace_TraceId_google_trace_TraceContext)
-#endif
-
-#if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
-/* If you get an error here, it means that you need to define PB_FIELD_16BIT
- * compile-time option. You can do that in pb.h or on compiler command line.
- * 
- * The reason you need to do this is that some of your messages contain tag
- * numbers or field sizes that are larger than what can fit in the default
- * 8 bit descriptors.
- */
-PB_STATIC_ASSERT((pb_membersize(google_trace_TraceContext, trace_id) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_google_trace_TraceId_google_trace_TraceContext)
-#endif
-
 
+/* @@protoc_insertion_point(eof) */

src/core/ext/census/gen/trace_context.pb.h

@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2016, Google Inc.
+ * Copyright 2017, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,11 +31,13 @@
  *
  */
 /* Automatically generated nanopb header */
-/* Generated by nanopb-0.3.5-dev */
+/* Generated by nanopb-0.3.7-dev at Fri Jan 20 16:14:22 2017. */
 
 #ifndef GRPC_CORE_EXT_CENSUS_GEN_TRACE_CONTEXT_PB_H
 #define GRPC_CORE_EXT_CENSUS_GEN_TRACE_CONTEXT_PB_H
 #include "third_party/nanopb/pb.h"
+
+/* @@protoc_insertion_point(includes) */
 #if PB_PROTO_HEADER_VERSION != 30
 #error Regenerate this file with the current version of nanopb generator.
 #endif
@@ -45,44 +47,35 @@ extern "C" {
 #endif
 
 /* Struct definitions */
-typedef struct _google_trace_TraceId {
-    bool has_hi;
-    uint64_t hi;
-    bool has_lo;
-    uint64_t lo;
-} google_trace_TraceId;
-
 typedef struct _google_trace_TraceContext {
-    bool has_trace_id;
-    google_trace_TraceId trace_id;
+    bool has_trace_id_hi;
+    uint64_t trace_id_hi;
+    bool has_trace_id_lo;
+    uint64_t trace_id_lo;
     bool has_span_id;
     uint64_t span_id;
-    bool has_is_sampled;
-    bool is_sampled;
+    bool has_span_options;
+    uint32_t span_options;
+/* @@protoc_insertion_point(struct:google_trace_TraceContext) */
 } google_trace_TraceContext;
 
 /* Default values for struct fields */
 
 /* Initializer values for message structs */
-#define google_trace_TraceId_init_default        {false, 0, false, 0}
-#define google_trace_TraceContext_init_default   {false, google_trace_TraceId_init_default, false, 0, false, 0}
-#define google_trace_TraceId_init_zero           {false, 0, false, 0}
-#define google_trace_TraceContext_init_zero      {false, google_trace_TraceId_init_zero, false, 0, false, 0}
+#define google_trace_TraceContext_init_default   {false, 0, false, 0, false, 0, false, 0}
+#define google_trace_TraceContext_init_zero      {false, 0, false, 0, false, 0, false, 0}
 
 /* Field tags (for use in manual encoding/decoding) */
-#define google_trace_TraceId_hi_tag              1
-#define google_trace_TraceId_lo_tag              2
-#define google_trace_TraceContext_trace_id_tag   1
-#define google_trace_TraceContext_span_id_tag    2
-#define google_trace_TraceContext_is_sampled_tag 3
+#define google_trace_TraceContext_trace_id_hi_tag 1
+#define google_trace_TraceContext_trace_id_lo_tag 2
+#define google_trace_TraceContext_span_id_tag    3
+#define google_trace_TraceContext_span_options_tag 4
 
 /* Struct field encoding specification for nanopb */
-extern const pb_field_t google_trace_TraceId_fields[3];
-extern const pb_field_t google_trace_TraceContext_fields[4];
+extern const pb_field_t google_trace_TraceContext_fields[5];
 
 /* Maximum encoded size of messages (where known) */
-#define google_trace_TraceId_size                18
-#define google_trace_TraceContext_size           31
+#define google_trace_TraceContext_size           32
 
 /* Message IDs (where set with "msgid" option) */
 #ifdef PB_MSGID
@@ -95,5 +88,6 @@ extern const pb_field_t google_trace_TraceContext_fields[4];
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
+/* @@protoc_insertion_point(eof) */
 
-#endif /* GRPC_CORE_EXT_CENSUS_GEN_TRACE_CONTEXT_PB_H */
+#endif

src/core/ext/census/trace_context.c

@@ -73,7 +73,7 @@ bool decode_trace_context(google_trace_TraceContext *ctxt, uint8_t *buffer,
   }
 
   // check fields
-  if (!ctxt->has_trace_id) {
+  if (!ctxt->has_trace_id_hi || !ctxt->has_trace_id_lo) {
     gpr_log(GPR_DEBUG, "Invalid TraceContext: missing trace_id");
     return false;
   }

src/core/ext/census/trace_context.h

@@ -38,6 +38,9 @@
 
 #include "src/core/ext/census/gen/trace_context.pb.h"
 
+/* Span option flags. */
+#define SPAN_OPTIONS_IS_SAMPLED 0x01
+
 /* Maximum number of bytes required to encode a TraceContext (31)
 1 byte for trace_id field
 1 byte for trace_id length

src/core/ext/census/trace_label.h

@@ -0,0 +1,61 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_CENSUS_TRACE_LABEL_H
+#define GRPC_CORE_EXT_CENSUS_TRACE_LABEL_H
+
+#include "src/core/ext/census/trace_string.h"
+
+/* Trace label (key/value pair) stores a label name and the label value. The
+   value can be one of trace_string/int64_t/bool. */
+typedef struct trace_label {
+  trace_string key;
+  enum label_type {
+    /* Unknown value for debugging/error purposes */
+    LABEL_UNKNOWN = 0,
+    /* A string value */
+    LABEL_STRING = 1,
+    /* An integer value. */
+    LABEL_INT = 2,
+    /* A boolean value. */
+    LABEL_BOOL = 3,
+  } value_type;
+
+  union value {
+    trace_string label_str;
+    int64_t label_int;
+    bool label_bool;
+  } value;
+} trace_label;
+
+#endif

src/core/ext/census/trace_propagation.h

@@ -0,0 +1,63 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_CENSUS_TRACE_PROPAGATION_H
+#define GRPC_CORE_EXT_CENSUS_TRACE_PROPAGATION_H
+
+#include "src/core/ext/census/tracing.h"
+
+/* Encoding and decoding functions for receiving and sending trace contexts
+   over the wire.  Only RPC libraries should be calling these
+   functions.  These functions return the number of bytes encoded/decoded
+   (0 if a failure has occurred). buf_size indicates the size of the
+   input/output buffer. trace_span_context is a struct that includes the
+   trace ID, span ID, and a set of option flags (is_sampled, etc.). */
+
+/* Converts a span context to a binary byte buffer. */
+size_t trace_span_context_to_binary(const trace_span_context *ctxt,
+                                    uint8_t *buf, size_t buf_size);
+
+/* Reads a binary byte buffer and populates a span context structure. */
+size_t binary_to_trace_span_context(const uint8_t *buf, size_t buf_size,
+                                    trace_span_context *ctxt);
+
+/* Converts a span context to an http metadata compatible string. */
+size_t trace_span_context_to_http_format(const trace_span_context *ctxt,
+                                         char *buf, size_t buf_size);
+
+/* Reads an http metadata compatible string and populates a span context
+   structure. */
+size_t http_format_to_trace_span_context(const char *buf, size_t buf_size,
+                                         trace_span_context *ctxt);
+
+#endif

src/core/ext/census/trace_status.h

@@ -0,0 +1,45 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_CENSUS_TRACE_STATUS_H
+#define GRPC_CORE_EXT_CENSUS_TRACE_STATUS_H
+
+#include "src/core/ext/census/trace_string.h"
+
+/* Stores a status code and status message for a trace. */
+typedef struct trace_status {
+  int64_t errorCode;
+  trace_string errorMessage;
+} trace_status;
+
+#endif

src/core/ext/census/trace_string.h

@@ -0,0 +1,50 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_CENSUS_TRACE_STRING_H
+#define GRPC_CORE_EXT_CENSUS_TRACE_STRING_H
+
+#include <grpc/slice.h>
+
+/* String struct for tracing messages. Since this is a C API, we do not have
+   access to a string class.  This is intended for use by higher level
+   languages which wrap around the C API, as most of them have a string class.
+   This will also be more efficient when copying, as we have an explicitly
+   specified length.  Also, grpc_slice has reference counting which allows for
+   interning. */
+typedef struct trace_string {
+  char *string;
+  size_t length;
+} trace_string;
+
+#endif

src/core/ext/census/tracing.c

@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,21 +31,41 @@
  *
  */
 
-//#include "src/core/ext/census/tracing.h"
+#include "src/core/ext/census/tracing.h"
 
 #include <grpc/census.h>
-#include <stdlib.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <openssl/rand.h>
+#include "src/core/ext/census/mlog.h"
 
-/* TODO(aveitch): These are all placeholder implementations. */
+void trace_start_span(const trace_span_context *span_ctxt,
+                      const trace_string name, const start_span_options *opts,
+                      trace_span_context *new_span_ctxt,
+                      bool has_remote_parent) {
+  // Noop implementation.
+}
+
+void trace_add_span_annotation(const trace_string description,
+                               const trace_label *labels, const size_t n_labels,
+                               trace_span_context *span_ctxt) {
+  // Noop implementation.
+}
 
-int census_trace_mask(const census_context *context) {
-  abort();
-  return CENSUS_TRACE_MASK_NONE;
+void trace_add_span_network_event_annotation(const trace_string description,
+                                             const trace_label *labels,
+                                             const size_t n_labels,
+                                             const gpr_timespec timestamp,
+                                             bool sent, uint64_t id,
+                                             trace_span_context *span_ctxt) {
+  // Noop implementation.
 }
 
-void census_set_trace_mask(int trace_mask) { abort(); }
+void trace_add_span_labels(const trace_label *labels, const size_t n_labels,
+                           trace_span_context *span_ctxt) {
+  // Noop implementation.
+}
 
-void census_trace_print(census_context *context, uint32_t type,
-                        const char *buffer, size_t n) {
-  abort();
+void trace_end_span(const trace_status *status, trace_span_context *span_ctxt) {
+  // Noop implementation.
 }

src/core/ext/census/tracing.h

@@ -0,0 +1,124 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_CENSUS_TRACING_H
+#define GRPC_CORE_EXT_CENSUS_TRACING_H
+
+#include <grpc/support/time.h>
+#include <stdbool.h>
+#include "src/core/ext/census/trace_context.h"
+#include "src/core/ext/census/trace_label.h"
+#include "src/core/ext/census/trace_status.h"
+
+/* This is the low level tracing API that other languages will interface with.
+   This is not intended to be accessed by the end-user, therefore it has been
+   designed with performance in mind rather than ease of use. */
+
+/* The tracing level. */
+enum TraceLevel {
+  /* Annotations on this context will be silently discarded. */
+  NO_TRACING = 0,
+  /* Annotations will not be saved to a persistent store. They will be
+     available via local APIs only. This setting is not propagated to child
+     spans. */
+  TRANSIENT_TRACING = 1,
+  /* Annotations are recorded for the entire distributed trace and they are
+     saved to a persistent store. This setting is propagated to child spans. */
+  PERSISTENT_TRACING = 2,
+};
+
+typedef struct trace_span_context {
+  /* Trace span context stores Span ID, Trace ID, and option flags. */
+  /* Trace ID is 128 bits split into 2 64-bit chunks (hi and lo). */
+  uint64_t trace_id_hi;
+  uint64_t trace_id_lo;
+  /* Span ID is 64 bits. */
+  uint64_t span_id;
+  /* Span-options is 32-bit value which contains flag options. */
+  uint32_t span_options;
+} trace_span_context;
+
+typedef struct start_span_options {
+  /* If set, this will override the Span.local_start_time for the Span. */
+  gpr_timespec local_start_timestamp;
+
+  /* Linked spans can be used to identify spans that are linked to this span in
+     a different trace.  This can be used (for example) in batching operations,
+     where a single batch handler processes multiple requests from different
+     traces. If set, points to a list of Spans are linked to the created Span.*/
+  trace_span_context *linked_spans;
+  /* The number of linked spans. */
+  size_t n_linked_spans;
+} start_span_options;
+
+/* Create a new child Span (or root if parent is NULL), with parent being the
+   designated Span. The child span will have the provided name and starting
+   span options (optional). The bool has_remote_parent marks whether the
+   context refers to a remote parent span or not. */
+void trace_start_span(const trace_span_context *span_ctxt,
+                      const trace_string name, const start_span_options *opts,
+                      trace_span_context *new_span_ctxt,
+                      bool has_remote_parent);
+
+/* Add a new Annotation to the Span. Annotations consist of a description
+   (trace_string) and a set of n labels (trace_label).  This can be populated
+   with arbitrary user data. */
+void trace_add_span_annotation(const trace_string description,
+                               const trace_label *labels, const size_t n_labels,
+                               trace_span_context *span_ctxt);
+
+/* Add a new NetworkEvent annotation to a Span. This function is only intended
+  to be used by RPC systems (either client or server), not by higher level
+  applications. The timestamp type will be system-defined, the sent argument
+  designates whether this is a network send event (client request, server
+  reply)or receive (server request, client reply). The id argument corresponds
+  to Span.Annotation.NetworkEvent.id from the data model, and serves to uniquely
+  identify each network message. */
+void trace_add_span_network_event(const trace_string description,
+                                  const trace_label *labels,
+                                  const size_t n_labels,
+                                  const gpr_timespec timestamp, bool sent,
+                                  uint64_t id, trace_span_context *span_ctxt);
+
+/* Add a set of labels to the Span. These will correspond to the field
+Span.labels in the data model. */
+void trace_add_span_labels(const trace_label *labels, const size_t n_labels,
+                           trace_span_context *span_ctxt);
+
+/* Mark the end of Span Execution with the given status. Only the timing of the
+first EndSpan call for a given Span will be recorded, and implementations are
+free to ignore all further calls using the Span. EndSpanOptions can
+optionally be NULL. */
+void trace_end_span(const trace_status *status, trace_span_context *span_ctxt);
+
+#endif

src/core/ext/client_channel/client_channel.c

@@ -44,8 +44,8 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/ext/client_channel/http_connect_handshaker.h"
-#include "src/core/ext/client_channel/http_proxy.h"
 #include "src/core/ext/client_channel/lb_policy_registry.h"
+#include "src/core/ext/client_channel/proxy_mapper_registry.h"
 #include "src/core/ext/client_channel/resolver_registry.h"
 #include "src/core/ext/client_channel/subchannel.h"
 #include "src/core/lib/channel/channel_args.h"
@@ -153,10 +153,6 @@ static void *method_parameters_create_from_json(const grpc_json *json) {
  */
 
 typedef struct client_channel_channel_data {
-  /** server name */
-  char *server_name;
-  /** HTTP CONNECT proxy to use, if any */
-  char *proxy_name;
   /** resolver for this channel */
   grpc_resolver *resolver;
   /** have we started resolving this channel */
@@ -317,17 +313,6 @@ static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
     // Use pick_first if nothing was specified and we didn't select grpclb
     // above.
     if (lb_policy_name == NULL) lb_policy_name = "pick_first";
-    // If using a proxy, add channel arg for server in HTTP CONNECT request.
-    if (chand->proxy_name != NULL) {
-      grpc_arg new_arg;
-      new_arg.key = GRPC_ARG_HTTP_CONNECT_SERVER;
-      new_arg.type = GRPC_ARG_STRING;
-      new_arg.value.string = chand->server_name;
-      grpc_channel_args *tmp_args = chand->resolver_result;
-      chand->resolver_result =
-          grpc_channel_args_copy_and_add(chand->resolver_result, &new_arg, 1);
-      grpc_channel_args_destroy(exec_ctx, tmp_args);
-    }
     // Instantiate LB policy.
     grpc_lb_policy_args lb_policy_args;
     lb_policy_args.args = chand->resolver_result;
@@ -542,16 +527,21 @@ static grpc_error *cc_init_channel_elem(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(arg->type == GRPC_ARG_POINTER);
   grpc_client_channel_factory_ref(arg->value.pointer.p);
   chand->client_channel_factory = arg->value.pointer.p;
-  // Instantiate resolver.
+  // Get server name to resolve, using proxy mapper if needed.
   arg = grpc_channel_args_find(args->channel_args, GRPC_ARG_SERVER_URI);
   GPR_ASSERT(arg != NULL);
   GPR_ASSERT(arg->type == GRPC_ARG_STRING);
-  chand->server_name = gpr_strdup(arg->value.string);
-  chand->proxy_name = grpc_get_http_proxy_server();
-  char *name_to_resolve =
-      chand->proxy_name == NULL ? chand->server_name : chand->proxy_name;
+  char *proxy_name = NULL;
+  grpc_channel_args *new_args = NULL;
+  grpc_proxy_mappers_map_name(exec_ctx, arg->value.string, args->channel_args,
+                              &proxy_name, &new_args);
+  // Instantiate resolver.
   chand->resolver = grpc_resolver_create(
-      exec_ctx, name_to_resolve, args->channel_args, chand->interested_parties);
+      exec_ctx, proxy_name != NULL ? proxy_name : arg->value.string,
+      new_args != NULL ? new_args : args->channel_args,
+      chand->interested_parties);
+  if (proxy_name != NULL) gpr_free(proxy_name);
+  if (new_args != NULL) grpc_channel_args_destroy(exec_ctx, new_args);
   if (chand->resolver == NULL) {
     return GRPC_ERROR_CREATE("resolver creation failed");
   }
@@ -562,8 +552,6 @@ static grpc_error *cc_init_channel_elem(grpc_exec_ctx *exec_ctx,
 static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                     grpc_channel_element *elem) {
   channel_data *chand = elem->channel_data;
-  gpr_free(chand->server_name);
-  gpr_free(chand->proxy_name);
   if (chand->resolver != NULL) {
     grpc_resolver_shutdown(exec_ctx, chand->resolver);
     GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel");
@@ -644,6 +632,12 @@ typedef struct client_channel_call_data {
   grpc_linked_mdelem lb_token_mdelem;
 } call_data;
 
+grpc_subchannel_call *grpc_client_channel_get_subchannel_call(
+    grpc_call_element *call_elem) {
+  grpc_subchannel_call *scc = GET_CALL((call_data *)call_elem->call_data);
+  return scc == CANCELLED_CALL ? NULL : scc;
+}
+
 static void add_waiting_locked(call_data *calld, grpc_transport_stream_op *op) {
   GPR_TIMER_BEGIN("add_waiting_locked", 0);
   if (calld->waiting_ops_count == calld->waiting_ops_capacity) {

src/core/ext/client_channel/client_channel.h

@@ -57,4 +57,8 @@ void grpc_client_channel_watch_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
     grpc_connectivity_state *state, grpc_closure *on_complete);
 
+/* Debug helper: pull the subchannel call from a call stack element */
+grpc_subchannel_call *grpc_client_channel_get_subchannel_call(
+    grpc_call_element *elem);
+
 #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_CLIENT_CHANNEL_H */

src/core/ext/client_channel/client_channel_plugin.c

@@ -39,6 +39,7 @@
 
 #include "src/core/ext/client_channel/client_channel.h"
 #include "src/core/ext/client_channel/http_connect_handshaker.h"
+#include "src/core/ext/client_channel/http_proxy.h"
 #include "src/core/ext/client_channel/lb_policy_registry.h"
 #include "src/core/ext/client_channel/proxy_mapper_registry.h"
 #include "src/core/ext/client_channel/resolver_registry.h"
@@ -82,6 +83,7 @@ void grpc_client_channel_init(void) {
   grpc_lb_policy_registry_init();
   grpc_resolver_registry_init();
   grpc_proxy_mapper_registry_init();
+  grpc_register_http_proxy_mapper();
   grpc_subchannel_index_init();
   grpc_channel_init_register_stage(GRPC_CLIENT_CHANNEL, INT_MIN,
                                    set_default_host_if_unset, NULL);

src/core/ext/client_channel/http_proxy.c

@@ -40,10 +40,13 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/ext/client_channel/http_connect_handshaker.h"
+#include "src/core/ext/client_channel/proxy_mapper_registry.h"
 #include "src/core/ext/client_channel/uri_parser.h"
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/support/env.h"
 
-char* grpc_get_http_proxy_server() {
+static char* grpc_get_http_proxy_server() {
   char* uri_str = gpr_getenv("http_proxy");
   if (uri_str == NULL) return NULL;
   grpc_uri* uri = grpc_uri_parse(uri_str, false /* suppress_errors */);
@@ -66,3 +69,55 @@ done:
   grpc_uri_destroy(uri);
   return proxy_name;
 }
+
+static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
+                                  grpc_proxy_mapper* mapper,
+                                  const char* server_uri,
+                                  const grpc_channel_args* args,
+                                  char** name_to_resolve,
+                                  grpc_channel_args** new_args) {
+  *name_to_resolve = grpc_get_http_proxy_server();
+  if (*name_to_resolve == NULL) return false;
+  grpc_uri* uri = grpc_uri_parse(server_uri, false /* suppress_errors */);
+  if (uri == NULL || uri->path[0] == '\0') {
+    gpr_log(GPR_ERROR,
+            "'http_proxy' environment variable set, but cannot "
+            "parse server URI '%s' -- not using proxy",
+            server_uri);
+    if (uri != NULL) grpc_uri_destroy(uri);
+    return false;
+  }
+  if (strcmp(uri->scheme, "unix") == 0) {
+    gpr_log(GPR_INFO, "not using proxy for Unix domain socket '%s'",
+            server_uri);
+    grpc_uri_destroy(uri);
+    return false;
+  }
+  grpc_arg new_arg;
+  new_arg.key = GRPC_ARG_HTTP_CONNECT_SERVER;
+  new_arg.type = GRPC_ARG_STRING;
+  new_arg.value.string = uri->path[0] == '/' ? uri->path + 1 : uri->path;
+  *new_args = grpc_channel_args_copy_and_add(args, &new_arg, 1);
+  grpc_uri_destroy(uri);
+  return true;
+}
+
+static bool proxy_mapper_map_address(grpc_exec_ctx* exec_ctx,
+                                     grpc_proxy_mapper* mapper,
+                                     const grpc_resolved_address* address,
+                                     const grpc_channel_args* args,
+                                     grpc_resolved_address** new_address,
+                                     grpc_channel_args** new_args) {
+  return false;
+}
+
+static void proxy_mapper_destroy(grpc_proxy_mapper* mapper) {}
+
+static const grpc_proxy_mapper_vtable proxy_mapper_vtable = {
+    proxy_mapper_map_name, proxy_mapper_map_address, proxy_mapper_destroy};
+
+static grpc_proxy_mapper proxy_mapper = {&proxy_mapper_vtable};
+
+void grpc_register_http_proxy_mapper() {
+  grpc_proxy_mapper_register(true /* at_start */, &proxy_mapper);
+}

src/core/ext/client_channel/http_proxy.h

@@ -34,8 +34,6 @@
 #ifndef GRPC_CORE_EXT_CLIENT_CHANNEL_HTTP_PROXY_H
 #define GRPC_CORE_EXT_CLIENT_CHANNEL_HTTP_PROXY_H
 
-/// Returns the name of the proxy to use, or NULL if no proxy is configured.
-/// Caller takes ownership of result.
-char* grpc_get_http_proxy_server();
+void grpc_register_http_proxy_mapper();
 
 #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_HTTP_PROXY_H */

src/core/ext/client_channel/proxy_mapper.c

@@ -38,13 +38,24 @@ void grpc_proxy_mapper_init(const grpc_proxy_mapper_vtable* vtable,
   mapper->vtable = vtable;
 }
 
-bool grpc_proxy_mapper_map(grpc_exec_ctx* exec_ctx, grpc_proxy_mapper* mapper,
-                           const grpc_resolved_address* address,
-                           const grpc_channel_args* args,
-                           grpc_resolved_address** new_address,
-                           grpc_channel_args** new_args) {
-  return mapper->vtable->map(exec_ctx, mapper, address, args, new_address,
-                             new_args);
+bool grpc_proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
+                                grpc_proxy_mapper* mapper,
+                                const char* server_uri,
+                                const grpc_channel_args* args,
+                                char** name_to_resolve,
+                                grpc_channel_args** new_args) {
+  return mapper->vtable->map_name(exec_ctx, mapper, server_uri, args,
+                                  name_to_resolve, new_args);
+}
+
+bool grpc_proxy_mapper_map_address(grpc_exec_ctx* exec_ctx,
+                                   grpc_proxy_mapper* mapper,
+                                   const grpc_resolved_address* address,
+                                   const grpc_channel_args* args,
+                                   grpc_resolved_address** new_address,
+                                   grpc_channel_args** new_args) {
+  return mapper->vtable->map_address(exec_ctx, mapper, address, args,
+                                     new_address, new_args);
 }
 
 void grpc_proxy_mapper_destroy(grpc_proxy_mapper* mapper) {

src/core/ext/client_channel/proxy_mapper.h

@@ -43,15 +43,22 @@
 typedef struct grpc_proxy_mapper grpc_proxy_mapper;
 
 typedef struct {
+  /// Determines the proxy name to resolve for \a server_uri.
+  /// If no proxy is needed, returns false.
+  /// Otherwise, sets \a name_to_resolve, optionally sets \a new_args,
+  /// and returns true.
+  bool (*map_name)(grpc_exec_ctx* exec_ctx, grpc_proxy_mapper* mapper,
+                   const char* server_uri, const grpc_channel_args* args,
+                   char** name_to_resolve, grpc_channel_args** new_args);
   /// Determines the proxy address to use to contact \a address.
   /// If no proxy is needed, returns false.
   /// Otherwise, sets \a new_address, optionally sets \a new_args, and
   /// returns true.
-  bool (*map)(grpc_exec_ctx* exec_ctx, grpc_proxy_mapper* mapper,
-              const grpc_resolved_address* address,
-              const grpc_channel_args* args,
-              grpc_resolved_address** new_address,
-              grpc_channel_args** new_args);
+  bool (*map_address)(grpc_exec_ctx* exec_ctx, grpc_proxy_mapper* mapper,
+                      const grpc_resolved_address* address,
+                      const grpc_channel_args* args,
+                      grpc_resolved_address** new_address,
+                      grpc_channel_args** new_args);
   /// Destroys \a mapper.
   void (*destroy)(grpc_proxy_mapper* mapper);
 } grpc_proxy_mapper_vtable;
@@ -63,11 +70,20 @@ struct grpc_proxy_mapper {
 void grpc_proxy_mapper_init(const grpc_proxy_mapper_vtable* vtable,
                             grpc_proxy_mapper* mapper);
 
-bool grpc_proxy_mapper_map(grpc_exec_ctx* exec_ctx, grpc_proxy_mapper* mapper,
-                           const grpc_resolved_address* address,
-                           const grpc_channel_args* args,
-                           grpc_resolved_address** new_address,
-                           grpc_channel_args** new_args);
+bool grpc_proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
+                                grpc_proxy_mapper* mapper,
+                                const char* server_uri,
+                                const grpc_channel_args* args,
+                                char** name_to_resolve,
+                                grpc_channel_args** new_args);
+
+bool grpc_proxy_mapper_map_address(grpc_exec_ctx* exec_ctx,
+                                   grpc_proxy_mapper* mapper,
+                                   const grpc_resolved_address* address,
+                                   const grpc_channel_args* args,
+                                   grpc_resolved_address** new_address,
+                                   grpc_channel_args** new_args);
+
 void grpc_proxy_mapper_destroy(grpc_proxy_mapper* mapper);
 
 #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_PROXY_MAPPER_H */

src/core/ext/client_channel/proxy_mapper_registry.c

@@ -61,15 +61,28 @@ static void grpc_proxy_mapper_list_register(grpc_proxy_mapper_list* list,
   ++list->num_mappers;
 }
 
-static bool grpc_proxy_mapper_list_map(grpc_exec_ctx* exec_ctx,
-                                       grpc_proxy_mapper_list* list,
-                                       const grpc_resolved_address* address,
-                                       const grpc_channel_args* args,
-                                       grpc_resolved_address** new_address,
-                                       grpc_channel_args** new_args) {
+static bool grpc_proxy_mapper_list_map_name(grpc_exec_ctx* exec_ctx,
+                                            grpc_proxy_mapper_list* list,
+                                            const char* server_uri,
+                                            const grpc_channel_args* args,
+                                            char** name_to_resolve,
+                                            grpc_channel_args** new_args) {
   for (size_t i = 0; i < list->num_mappers; ++i) {
-    if (grpc_proxy_mapper_map(exec_ctx, list->list[i], address, args,
-                              new_address, new_args)) {
+    if (grpc_proxy_mapper_map_name(exec_ctx, list->list[i], server_uri, args,
+                                   name_to_resolve, new_args)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static bool grpc_proxy_mapper_list_map_address(
+    grpc_exec_ctx* exec_ctx, grpc_proxy_mapper_list* list,
+    const grpc_resolved_address* address, const grpc_channel_args* args,
+    grpc_resolved_address** new_address, grpc_channel_args** new_args) {
+  for (size_t i = 0; i < list->num_mappers; ++i) {
+    if (grpc_proxy_mapper_map_address(exec_ctx, list->list[i], address, args,
+                                      new_address, new_args)) {
       return true;
     }
   }
@@ -101,11 +114,20 @@ void grpc_proxy_mapper_register(bool at_start, grpc_proxy_mapper* mapper) {
   grpc_proxy_mapper_list_register(&g_proxy_mapper_list, at_start, mapper);
 }
 
-bool grpc_proxy_mappers_map(grpc_exec_ctx* exec_ctx,
-                            const grpc_resolved_address* address,
-                            const grpc_channel_args* args,
-                            grpc_resolved_address** new_address,
-                            grpc_channel_args** new_args) {
-  return grpc_proxy_mapper_list_map(exec_ctx, &g_proxy_mapper_list, address,
-                                    args, new_address, new_args);
+bool grpc_proxy_mappers_map_name(grpc_exec_ctx* exec_ctx,
+                                 const char* server_uri,
+                                 const grpc_channel_args* args,
+                                 char** name_to_resolve,
+                                 grpc_channel_args** new_args) {
+  return grpc_proxy_mapper_list_map_name(exec_ctx, &g_proxy_mapper_list,
+                                         server_uri, args, name_to_resolve,
+                                         new_args);
+}
+bool grpc_proxy_mappers_map_address(grpc_exec_ctx* exec_ctx,
+                                    const grpc_resolved_address* address,
+                                    const grpc_channel_args* args,
+                                    grpc_resolved_address** new_address,
+                                    grpc_channel_args** new_args) {
+  return grpc_proxy_mapper_list_map_address(
+      exec_ctx, &g_proxy_mapper_list, address, args, new_address, new_args);
 }

src/core/ext/client_channel/proxy_mapper_registry.h

@@ -44,10 +44,16 @@ void grpc_proxy_mapper_registry_shutdown();
 /// the list.  Otherwise, it will be added to the end.
 void grpc_proxy_mapper_register(bool at_start, grpc_proxy_mapper* mapper);
 
-bool grpc_proxy_mappers_map(grpc_exec_ctx* exec_ctx,
-                            const grpc_resolved_address* address,
-                            const grpc_channel_args* args,
-                            grpc_resolved_address** new_address,
-                            grpc_channel_args** new_args);
+bool grpc_proxy_mappers_map_name(grpc_exec_ctx* exec_ctx,
+                                 const char* server_uri,
+                                 const grpc_channel_args* args,
+                                 char** name_to_resolve,
+                                 grpc_channel_args** new_args);
+
+bool grpc_proxy_mappers_map_address(grpc_exec_ctx* exec_ctx,
+                                    const grpc_resolved_address* address,
+                                    const grpc_channel_args* args,
+                                    grpc_resolved_address** new_address,
+                                    grpc_channel_args** new_args);
 
 #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_PROXY_MAPPER_REGISTRY_H */

src/core/ext/client_channel/subchannel.c

@@ -336,8 +336,8 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
   grpc_set_initial_connect_string(&addr, &c->initial_connect_string);
   grpc_resolved_address *new_address = NULL;
   grpc_channel_args *new_args = NULL;
-  if (grpc_proxy_mappers_map(exec_ctx, addr, args->args, &new_address,
-                             &new_args)) {
+  if (grpc_proxy_mappers_map_address(exec_ctx, addr, args->args, &new_address,
+                                     &new_args)) {
     GPR_ASSERT(new_address != NULL);
     gpr_free(addr);
     addr = new_address;
@@ -788,7 +788,8 @@ grpc_call_stack *grpc_subchannel_call_get_call_stack(
   return SUBCHANNEL_CALL_TO_CALL_STACK(subchannel_call);
 }
 
-static void grpc_uri_to_sockaddr(char *uri_str, grpc_resolved_address *addr) {
+static void grpc_uri_to_sockaddr(const char *uri_str,
+                                 grpc_resolved_address *addr) {
   grpc_uri *uri = grpc_uri_parse(uri_str, 0 /* suppress_errors */);
   GPR_ASSERT(uri != NULL);
   if (strcmp(uri->scheme, "ipv4") == 0) {
@@ -803,14 +804,19 @@ static void grpc_uri_to_sockaddr(char *uri_str, grpc_resolved_address *addr) {
 
 void grpc_get_subchannel_address_arg(const grpc_channel_args *args,
                                      grpc_resolved_address *addr) {
+  const char *addr_uri_str = grpc_get_subchannel_address_uri_arg(args);
+  memset(addr, 0, sizeof(*addr));
+  if (*addr_uri_str != '\0') {
+    grpc_uri_to_sockaddr(addr_uri_str, addr);
+  }
+}
+
+const char *grpc_get_subchannel_address_uri_arg(const grpc_channel_args *args) {
   const grpc_arg *addr_arg =
       grpc_channel_args_find(args, GRPC_ARG_SUBCHANNEL_ADDRESS);
   GPR_ASSERT(addr_arg != NULL);  // Should have been set by LB policy.
   GPR_ASSERT(addr_arg->type == GRPC_ARG_STRING);
-  memset(addr, 0, sizeof(*addr));
-  if (*addr_arg->value.string != '\0') {
-    grpc_uri_to_sockaddr(addr_arg->value.string, addr);
-  }
+  return addr_arg->value.string;
 }
 
 grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address *addr) {

src/core/ext/client_channel/subchannel.h

@@ -178,6 +178,9 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
 void grpc_get_subchannel_address_arg(const grpc_channel_args *args,
                                      grpc_resolved_address *addr);
 
+/// Returns the URI string for the address to connect to.
+const char *grpc_get_subchannel_address_uri_arg(const grpc_channel_args *args);
+
 /// Returns a new channel arg encoding the subchannel address as a string.
 /// Caller is responsible for freeing the string.
 grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address *addr);

src/core/ext/lb_policy/grpclb/grpclb.c

@@ -112,11 +112,13 @@
 #include "src/core/ext/client_channel/lb_policy_registry.h"
 #include "src/core/ext/client_channel/parse_address.h"
 #include "src/core/ext/lb_policy/grpclb/grpclb.h"
+#include "src/core/ext/lb_policy/grpclb/grpclb_channel.h"
 #include "src/core/ext/lb_policy/grpclb/load_balancer_api.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/sockaddr.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/slice/slice_hash_table.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/backoff.h"
@@ -751,6 +753,96 @@ static void glb_rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
   GRPC_ERROR_UNREF(error);
 }
 
+static void destroy_balancer_name(grpc_exec_ctx *exec_ctx,
+                                  void *balancer_name) {
+  gpr_free(balancer_name);
+}
+
+static void *copy_balancer_name(void *balancer_name) {
+  return gpr_strdup(balancer_name);
+}
+
+static grpc_slice_hash_table_entry targets_info_entry_create(
+    const char *address, const char *balancer_name) {
+  static const grpc_slice_hash_table_vtable vtable = {destroy_balancer_name,
+                                                      copy_balancer_name};
+  grpc_slice_hash_table_entry entry;
+  entry.key = grpc_slice_from_copied_string(address);
+  entry.value = (void *)balancer_name;
+  entry.vtable = &vtable;
+  return entry;
+}
+
+/* Returns the target URI for the LB service whose addresses are in \a
+ * addresses.  Using this URI, a bidirectional streaming channel will be created
+ * for the reception of load balancing updates.
+ *
+ * The output argument \a targets_info will be updated to contain a mapping of
+ * "LB server address" to "balancer name", as reported by the naming system.
+ * This mapping will be propagated via the channel arguments of the
+ * aforementioned LB streaming channel, to be used by the security connector for
+ * secure naming checks. The user is responsible for freeing \a targets_info. */
+static char *get_lb_uri_target_addresses(grpc_exec_ctx *exec_ctx,
+                                         const grpc_lb_addresses *addresses,
+                                         grpc_slice_hash_table **targets_info) {
+  size_t num_grpclb_addrs = 0;
+  for (size_t i = 0; i < addresses->num_addresses; ++i) {
+    if (addresses->addresses[i].is_balancer) ++num_grpclb_addrs;
+  }
+  /* All input addresses come from a resolver that claims they are LB services.
+   * It's the resolver's responsibility to make sure this policy is only
+   * instantiated and used in that case. Otherwise, something has gone wrong. */
+  GPR_ASSERT(num_grpclb_addrs > 0);
+
+  grpc_slice_hash_table_entry *targets_info_entries =
+      gpr_malloc(sizeof(*targets_info_entries) * num_grpclb_addrs);
+
+  /* construct a target ipvX://ip1:port1,ip2:port2,... from the addresses in \a
+   * addresses */
+  /* TODO(dgq): support mixed ip version */
+  char **addr_strs = gpr_malloc(sizeof(char *) * num_grpclb_addrs);
+  size_t addr_index = 0;
+
+  for (size_t i = 0; i < addresses->num_addresses; i++) {
+    if (addresses->addresses[i].user_data != NULL) {
+      gpr_log(GPR_ERROR,
+              "This LB policy doesn't support user data. It will be ignored");
+    }
+    if (addresses->addresses[i].is_balancer) {
+      char *addr_str;
+      GPR_ASSERT(grpc_sockaddr_to_string(
+                     &addr_str, &addresses->addresses[i].address, true) > 0);
+      targets_info_entries[addr_index] = targets_info_entry_create(
+          addr_str, addresses->addresses[i].balancer_name);
+      addr_strs[addr_index++] = addr_str;
+    }
+  }
+  GPR_ASSERT(addr_index == num_grpclb_addrs);
+
+  size_t uri_path_len;
+  char *uri_path = gpr_strjoin_sep((const char **)addr_strs, num_grpclb_addrs,
+                                   ",", &uri_path_len);
+  for (size_t i = 0; i < num_grpclb_addrs; i++) gpr_free(addr_strs[i]);
+  gpr_free(addr_strs);
+
+  char *target_uri_str = NULL;
+  /* TODO(dgq): Don't assume all addresses will share the scheme of the first
+   * one */
+  gpr_asprintf(&target_uri_str, "%s:%s",
+               grpc_sockaddr_get_uri_scheme(&addresses->addresses[0].address),
+               uri_path);
+  gpr_free(uri_path);
+
+  *targets_info =
+      grpc_slice_hash_table_create(num_grpclb_addrs, targets_info_entries);
+  for (size_t i = 0; i < num_grpclb_addrs; i++) {
+    grpc_slice_unref_internal(exec_ctx, targets_info_entries[i].key);
+  }
+  gpr_free(targets_info_entries);
+
+  return target_uri_str;
+}
+
 static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
                                   grpc_lb_policy_factory *factory,
                                   grpc_lb_policy_args *args) {
@@ -788,85 +880,30 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
   }
   grpc_uri_destroy(uri);
 
-  /* All input addresses in addresses come from a resolver that claims
-   * they are LB services. It's the resolver's responsibility to make sure
-   * this policy is only instantiated and used in that case.
-   *
-   * Create a client channel over them to communicate with a LB service */
   glb_policy->cc_factory = args->client_channel_factory;
   glb_policy->args = grpc_channel_args_copy(args->args);
   GPR_ASSERT(glb_policy->cc_factory != NULL);
 
-  /* construct a target from the addresses in args, given in the form
-   * ipvX://ip1:port1,ip2:port2,...
-   * TODO(dgq): support mixed ip version */
-  char **addr_strs = gpr_malloc(sizeof(char *) * num_grpclb_addrs);
-  size_t addr_index = 0;
-  for (size_t i = 0; i < addresses->num_addresses; i++) {
-    if (addresses->addresses[i].user_data != NULL) {
-      gpr_log(GPR_ERROR,
-              "This LB policy doesn't support user data. It will be ignored");
-    }
-    if (addresses->addresses[i].is_balancer) {
-      if (addr_index == 0) {
-        addr_strs[addr_index++] =
-            grpc_sockaddr_to_uri(&addresses->addresses[i].address);
-      } else {
-        GPR_ASSERT(grpc_sockaddr_to_string(&addr_strs[addr_index++],
-                                           &addresses->addresses[i].address,
-                                           true) > 0);
-      }
-    }
-  }
-  size_t uri_path_len;
-  char *target_uri_str = gpr_strjoin_sep((const char **)addr_strs,
-                                         num_grpclb_addrs, ",", &uri_path_len);
-
-  /* Create a channel to talk to the LBs.
-   *
-   * We strip out the channel arg for the LB policy name, since we want
-   * to use the default (pick_first) in this case.
-   *
-   * We also strip out the channel arg for the resolved addresses, since
-   * that will be generated by the name resolver used in the LB channel.
-   * Note that the LB channel will use the sockaddr resolver, so this
-   * won't actually generate a query to DNS (or some other name service).
-   * However, the addresses returned by the sockaddr resolver will have
-   * is_balancer=false, whereas our own addresses have is_balancer=true.
-   * We need the LB channel to return addresses with is_balancer=false
-   * so that it does not wind up recursively using the grpclb LB policy,
-   * as per the special case logic in client_channel.c.
-   *
-   * Finally, we also strip out the channel arg for the server URI,
-   * since that will be different for the LB channel than for the parent
-   * channel.  (The client channel factory will re-add this arg with
-   * the right value.)
-   */
-  static const char *keys_to_remove[] = {
-      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI};
-  grpc_channel_args *new_args = grpc_channel_args_copy_and_remove(
-      args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove));
-  glb_policy->lb_channel = grpc_client_channel_factory_create_channel(
-      exec_ctx, glb_policy->cc_factory, target_uri_str,
-      GRPC_CLIENT_CHANNEL_TYPE_LOAD_BALANCING, new_args);
-  grpc_channel_args_destroy(exec_ctx, new_args);
-
-  gpr_free(target_uri_str);
-  for (size_t i = 0; i < num_grpclb_addrs; i++) {
-    gpr_free(addr_strs[i]);
-  }
-  gpr_free(addr_strs);
-
+  grpc_slice_hash_table *targets_info = NULL;
+  /* Create a client channel over them to communicate with a LB service */
+  char *lb_service_target_addresses =
+      get_lb_uri_target_addresses(exec_ctx, addresses, &targets_info);
+  grpc_channel_args *lb_channel_args =
+      get_lb_channel_args(exec_ctx, targets_info, args->args);
+  glb_policy->lb_channel = grpc_lb_policy_grpclb_create_lb_channel(
+      exec_ctx, lb_service_target_addresses, args->client_channel_factory,
+      lb_channel_args);
+  grpc_slice_hash_table_unref(exec_ctx, targets_info);
+  grpc_channel_args_destroy(exec_ctx, lb_channel_args);
+  gpr_free(lb_service_target_addresses);
   if (glb_policy->lb_channel == NULL) {
     gpr_free(glb_policy);
     return NULL;
   }
-
   grpc_lb_policy_init(&glb_policy->base, &glb_lb_policy_vtable);
   gpr_mu_init(&glb_policy->mu);
   grpc_connectivity_state_init(&glb_policy->state_tracker, GRPC_CHANNEL_IDLE,
                                "grpclb");
-
   return &glb_policy->base;
 }
 

src/core/ext/lb_policy/grpclb/grpclb_channel.c

@@ -0,0 +1,77 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/lb_policy/grpclb/grpclb_channel.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/sockaddr_utils.h"
+#include "src/core/lib/support/string.h"
+
+grpc_channel *grpc_lb_policy_grpclb_create_lb_channel(
+    grpc_exec_ctx *exec_ctx, const char *lb_service_target_addresses,
+    grpc_client_channel_factory *client_channel_factory,
+    grpc_channel_args *args) {
+  grpc_channel *lb_channel = grpc_client_channel_factory_create_channel(
+      exec_ctx, client_channel_factory, lb_service_target_addresses,
+      GRPC_CLIENT_CHANNEL_TYPE_LOAD_BALANCING, args);
+  return lb_channel;
+}
+
+grpc_channel_args *get_lb_channel_args(grpc_exec_ctx *exec_ctx,
+                                       grpc_slice_hash_table *targets_info,
+                                       const grpc_channel_args *args) {
+  /* We strip out the channel arg for the LB policy name, since we want
+   * to use the default (pick_first) in this case.
+   *
+   * We also strip out the channel arg for the resolved addresses, since
+   * that will be generated by the name resolver used in the LB channel.
+   * Note that the LB channel will use the sockaddr resolver, so this
+   * won't actually generate a query to DNS (or some other name service).
+   * However, the addresses returned by the sockaddr resolver will have
+   * is_balancer=false, whereas our own addresses have is_balancer=true.
+   * We need the LB channel to return addresses with is_balancer=false
+   * so that it does not wind up recursively using the grpclb LB policy,
+   * as per the special case logic in client_channel.c.
+   *
+   * Lastly, we also strip out the channel arg for the server URI,
+   * since that will be different for the LB channel than for the parent
+   * channel (the client channel factory will re-add this arg with
+   * the right value). */
+  static const char *keys_to_remove[] = {
+      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI};
+  return grpc_channel_args_copy_and_remove(args, keys_to_remove,
+                                           GPR_ARRAY_SIZE(keys_to_remove));
+}

src/core/ext/lb_policy/grpclb/grpclb_channel.h

@@ -0,0 +1,56 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_LB_POLICY_GRPCLB_GRPCLB_CHANNEL_H
+#define GRPC_CORE_EXT_LB_POLICY_GRPCLB_GRPCLB_CHANNEL_H
+
+#include "src/core/ext/client_channel/lb_policy_factory.h"
+#include "src/core/lib/slice/slice_hash_table.h"
+
+/** Create the channel used for communicating with an LB service.
+ * Note that an LB *service* may be comprised of several LB *servers*.
+ *
+ * \a lb_service_target_addresses is the target URI containing the addresses
+ * from resolving the LB service's name (eg, ipv4:10.0.0.1:1234,10.2.3.4:9876).
+ * \a client_channel_factory will be used for the creation of the LB channel,
+ * alongside the channel args passed in \a args. */
+grpc_channel *grpc_lb_policy_grpclb_create_lb_channel(
+    grpc_exec_ctx *exec_ctx, const char *lb_service_target_addresses,
+    grpc_client_channel_factory *client_channel_factory,
+    grpc_channel_args *args);
+
+grpc_channel_args *get_lb_channel_args(grpc_exec_ctx *exec_ctx,
+                                       grpc_slice_hash_table *targets_info,
+                                       const grpc_channel_args *args);
+
+#endif /* GRPC_CORE_EXT_LB_POLICY_GRPCLB_GRPCLB_CHANNEL_H */

src/core/ext/lb_policy/grpclb/grpclb_channel_secure.c

@@ -0,0 +1,107 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/lb_policy/grpclb/grpclb_channel.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/sockaddr_utils.h"
+#include "src/core/lib/security/credentials/credentials.h"
+#include "src/core/lib/security/transport/lb_targets_info.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/support/string.h"
+
+grpc_channel *grpc_lb_policy_grpclb_create_lb_channel(
+    grpc_exec_ctx *exec_ctx, const char *lb_service_target_addresses,
+    grpc_client_channel_factory *client_channel_factory,
+    grpc_channel_args *args) {
+  grpc_channel_args *new_args = args;
+  grpc_channel_credentials *channel_credentials =
+      grpc_channel_credentials_find_in_args(args);
+  if (channel_credentials != NULL) {
+    /* Substitute the channel credentials with a version without call
+     * credentials: the load balancer is not necessarily trusted to handle
+     * bearer token credentials */
+    static const char *keys_to_remove[] = {GRPC_ARG_CHANNEL_CREDENTIALS};
+    grpc_channel_credentials *creds_sans_call_creds =
+        grpc_channel_credentials_duplicate_without_call_credentials(
+            channel_credentials);
+    GPR_ASSERT(creds_sans_call_creds != NULL);
+    grpc_arg args_to_add[] = {
+        grpc_channel_credentials_to_arg(creds_sans_call_creds)};
+    /* Create the new set of channel args */
+    new_args = grpc_channel_args_copy_and_add_and_remove(
+        args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), args_to_add,
+        GPR_ARRAY_SIZE(args_to_add));
+    grpc_channel_credentials_unref(exec_ctx, creds_sans_call_creds);
+  }
+  grpc_channel *lb_channel = grpc_client_channel_factory_create_channel(
+      exec_ctx, client_channel_factory, lb_service_target_addresses,
+      GRPC_CLIENT_CHANNEL_TYPE_LOAD_BALANCING, new_args);
+  if (channel_credentials != NULL) {
+    grpc_channel_args_destroy(exec_ctx, new_args);
+  }
+  return lb_channel;
+}
+
+grpc_channel_args *get_lb_channel_args(grpc_exec_ctx *exec_ctx,
+                                       grpc_slice_hash_table *targets_info,
+                                       const grpc_channel_args *args) {
+  const grpc_arg targets_info_arg =
+      grpc_lb_targets_info_create_channel_arg(targets_info);
+  /* We strip out the channel arg for the LB policy name, since we want
+   * to use the default (pick_first) in this case.
+   *
+   * We also strip out the channel arg for the resolved addresses, since
+   * that will be generated by the name resolver used in the LB channel.
+   * Note that the LB channel will use the sockaddr resolver, so this
+   * won't actually generate a query to DNS (or some other name service).
+   * However, the addresses returned by the sockaddr resolver will have
+   * is_balancer=false, whereas our own addresses have is_balancer=true.
+   * We need the LB channel to return addresses with is_balancer=false
+   * so that it does not wind up recursively using the grpclb LB policy,
+   * as per the special case logic in client_channel.c.
+   *
+   * Lastly, we also strip out the channel arg for the server URI,
+   * since that will be different for the LB channel than for the parent
+   * channel (the client channel factory will re-add this arg with
+   * the right value). */
+  static const char *keys_to_remove[] = {
+      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI};
+  /* Add the targets info table to be used for secure naming */
+  return grpc_channel_args_copy_and_add_and_remove(
+      args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), &targets_info_arg,
+      1);
+}

src/core/ext/lb_policy/round_robin/round_robin.c

@@ -739,6 +739,13 @@ static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
     sc_args.args = new_args;
     grpc_subchannel *subchannel = grpc_client_channel_factory_create_subchannel(
         exec_ctx, args->client_channel_factory, &sc_args);
+    if (grpc_lb_round_robin_trace) {
+      char *address_uri =
+          grpc_sockaddr_to_uri(&addresses->addresses[i].address);
+      gpr_log(GPR_DEBUG, "Created subchannel %p for address uri %s",
+              (void *)subchannel, address_uri);
+      gpr_free(address_uri);
+    }
     grpc_channel_args_destroy(exec_ctx, new_args);
 
     if (subchannel != NULL) {

src/core/ext/transport/chttp2/client/insecure/channel_create.c

@@ -39,6 +39,7 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/client_channel/resolver_registry.h"
 #include "src/core/ext/transport/chttp2/client/chttp2_connector.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/surface/api_trace.h"
@@ -63,12 +64,17 @@ static grpc_channel *client_channel_factory_create_channel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const char *target, grpc_client_channel_type type,
     const grpc_channel_args *args) {
+  if (target == NULL) {
+    gpr_log(GPR_ERROR, "cannot create channel with NULL target name");
+    return NULL;
+  }
   // Add channel arg containing the server URI.
   grpc_arg arg;
   arg.type = GRPC_ARG_STRING;
   arg.key = GRPC_ARG_SERVER_URI;
-  arg.value.string = (char *)target;
+  arg.value.string = grpc_resolver_factory_add_default_prefix_if_needed(target);
   grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
+  gpr_free(arg.value.string);
   grpc_channel *channel = grpc_channel_create(exec_ctx, target, new_args,
                                               GRPC_CLIENT_CHANNEL, NULL);
   grpc_channel_args_destroy(exec_ctx, new_args);

src/core/ext/transport/chttp2/client/secure/secure_channel_create.c

@@ -39,10 +39,16 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/client_channel/resolver_registry.h"
+#include "src/core/ext/client_channel/uri_parser.h"
 #include "src/core/ext/transport/chttp2/client/chttp2_connector.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/security/credentials/credentials.h"
+#include "src/core/lib/security/transport/lb_targets_info.h"
 #include "src/core/lib/security/transport/security_connector.h"
+#include "src/core/lib/slice/slice_hash_table.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/channel.h"
 
@@ -52,12 +58,114 @@ static void client_channel_factory_ref(
 static void client_channel_factory_unref(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory) {}
 
+static grpc_subchannel_args *get_secure_naming_subchannel_args(
+    grpc_exec_ctx *exec_ctx, const grpc_subchannel_args *args) {
+  grpc_channel_credentials *channel_credentials =
+      grpc_channel_credentials_find_in_args(args->args);
+  if (channel_credentials == NULL) {
+    gpr_log(GPR_ERROR,
+            "Can't create subchannel: channel credentials missing for secure "
+            "channel.");
+    return NULL;
+  }
+  // Make sure security connector does not already exist in args.
+  if (grpc_security_connector_find_in_args(args->args) != NULL) {
+    gpr_log(GPR_ERROR,
+            "Can't create subchannel: security connector already present in "
+            "channel args.");
+    return NULL;
+  }
+  // To which address are we connecting? By default, use the server URI.
+  const grpc_arg *server_uri_arg =
+      grpc_channel_args_find(args->args, GRPC_ARG_SERVER_URI);
+  GPR_ASSERT(server_uri_arg != NULL);
+  GPR_ASSERT(server_uri_arg->type == GRPC_ARG_STRING);
+  const char *server_uri_str = server_uri_arg->value.string;
+  GPR_ASSERT(server_uri_str != NULL);
+  grpc_uri *server_uri =
+      grpc_uri_parse(server_uri_str, true /* supress errors */);
+  GPR_ASSERT(server_uri != NULL);
+  const char *server_uri_path;
+  server_uri_path =
+      server_uri->path[0] == '/' ? server_uri->path + 1 : server_uri->path;
+  const grpc_slice_hash_table *targets_info =
+      grpc_lb_targets_info_find_in_args(args->args);
+  char *target_name_to_check = NULL;
+  if (targets_info != NULL) {  // LB channel
+    // Find the balancer name for the target.
+    const char *target_uri_str =
+        grpc_get_subchannel_address_uri_arg(args->args);
+    grpc_uri *target_uri =
+        grpc_uri_parse(target_uri_str, false /* suppress errors */);
+    GPR_ASSERT(target_uri != NULL);
+    if (target_uri->path[0] != '\0') {  // "path" may be empty
+      const grpc_slice key = grpc_slice_from_static_string(
+          target_uri->path[0] == '/' ? target_uri->path + 1 : target_uri->path);
+      const char *value = grpc_slice_hash_table_get(targets_info, key);
+      if (value != NULL) target_name_to_check = gpr_strdup(value);
+      grpc_slice_unref_internal(exec_ctx, key);
+    }
+    if (target_name_to_check == NULL) {
+      // If the target name to check hasn't already been set, fall back to using
+      // SERVER_URI
+      target_name_to_check = gpr_strdup(server_uri_path);
+    }
+    grpc_uri_destroy(target_uri);
+  } else {  // regular channel: the secure name is the original server URI.
+    target_name_to_check = gpr_strdup(server_uri_path);
+  }
+  grpc_uri_destroy(server_uri);
+  GPR_ASSERT(target_name_to_check != NULL);
+  grpc_channel_security_connector *subchannel_security_connector = NULL;
+  // Create the security connector using the credentials and target name.
+  grpc_channel_args *new_args_from_connector = NULL;
+  const grpc_security_status security_status =
+      grpc_channel_credentials_create_security_connector(
+          exec_ctx, channel_credentials, target_name_to_check, args->args,
+          &subchannel_security_connector, &new_args_from_connector);
+  if (security_status != GRPC_SECURITY_OK) {
+    gpr_log(GPR_ERROR,
+            "Failed to create secure subchannel for secure name '%s'",
+            target_name_to_check);
+    gpr_free(target_name_to_check);
+    return NULL;
+  }
+  gpr_free(target_name_to_check);
+  grpc_arg new_security_connector_arg =
+      grpc_security_connector_to_arg(&subchannel_security_connector->base);
+
+  grpc_channel_args *new_args = grpc_channel_args_copy_and_add(
+      new_args_from_connector != NULL ? new_args_from_connector : args->args,
+      &new_security_connector_arg, 1);
+  GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, &subchannel_security_connector->base,
+                                "lb_channel_create");
+  if (new_args_from_connector != NULL) {
+    grpc_channel_args_destroy(exec_ctx, new_args_from_connector);
+  }
+  grpc_subchannel_args *final_sc_args = gpr_malloc(sizeof(*final_sc_args));
+  memcpy(final_sc_args, args, sizeof(*args));
+  final_sc_args->args = new_args;
+  return final_sc_args;
+}
+
 static grpc_subchannel *client_channel_factory_create_subchannel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const grpc_subchannel_args *args) {
+  grpc_subchannel_args *subchannel_args =
+      get_secure_naming_subchannel_args(exec_ctx, args);
+  if (subchannel_args == NULL) {
+    gpr_log(
+        GPR_ERROR,
+        "Failed to create subchannel arguments during subchannel creation.");
+    return NULL;
+  }
   grpc_connector *connector = grpc_chttp2_connector_create();
-  grpc_subchannel *s = grpc_subchannel_create(exec_ctx, connector, args);
+  grpc_subchannel *s =
+      grpc_subchannel_create(exec_ctx, connector, subchannel_args);
   grpc_connector_unref(exec_ctx, connector);
+  grpc_channel_args_destroy(exec_ctx,
+                            (grpc_channel_args *)subchannel_args->args);
+  gpr_free(subchannel_args);
   return s;
 }
 
@@ -65,12 +173,17 @@ static grpc_channel *client_channel_factory_create_channel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const char *target, grpc_client_channel_type type,
     const grpc_channel_args *args) {
+  if (target == NULL) {
+    gpr_log(GPR_ERROR, "cannot create channel with NULL target name");
+    return NULL;
+  }
   // Add channel arg containing the server URI.
   grpc_arg arg;
   arg.type = GRPC_ARG_STRING;
   arg.key = GRPC_ARG_SERVER_URI;
-  arg.value.string = (char *)target;
+  arg.value.string = grpc_resolver_factory_add_default_prefix_if_needed(target);
   grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
+  gpr_free(arg.value.string);
   grpc_channel *channel = grpc_channel_create(exec_ctx, target, new_args,
                                               GRPC_CLIENT_CHANNEL, NULL);
   grpc_channel_args_destroy(exec_ctx, new_args);
@@ -85,10 +198,10 @@ static const grpc_client_channel_factory_vtable client_channel_factory_vtable =
 static grpc_client_channel_factory client_channel_factory = {
     &client_channel_factory_vtable};
 
-/* Create a secure client channel:
-   Asynchronously: - resolve target
-                   - connect to it (trying alternatives as presented)
-                   - perform handshakes */
+// Create a secure client channel:
+//   Asynchronously: - resolve target
+//                   - connect to it (trying alternatives as presented)
+//                   - perform handshakes
 grpc_channel *grpc_secure_channel_create(grpc_channel_credentials *creds,
                                          const char *target,
                                          const grpc_channel_args *args,
@@ -97,46 +210,27 @@ grpc_channel *grpc_secure_channel_create(grpc_channel_credentials *creds,
   GRPC_API_TRACE(
       "grpc_secure_channel_create(creds=%p, target=%s, args=%p, "
       "reserved=%p)",
-      4, (creds, target, args, reserved));
+      4, ((void *)creds, target, (void *)args, (void *)reserved));
   GPR_ASSERT(reserved == NULL);
-  // Make sure security connector does not already exist in args.
-  if (grpc_find_security_connector_in_args(args) != NULL) {
-    gpr_log(GPR_ERROR, "Cannot set security context in channel args.");
+  grpc_channel *channel = NULL;
+  if (creds != NULL) {
+    // Add channel args containing the client channel factory and channel
+    // credentials.
+    grpc_arg args_to_add[] = {
+        grpc_client_channel_factory_create_channel_arg(&client_channel_factory),
+        grpc_channel_credentials_to_arg(creds)};
+    grpc_channel_args *new_args = grpc_channel_args_copy_and_add(
+        args, args_to_add, GPR_ARRAY_SIZE(args_to_add));
+    // Create channel.
+    channel = client_channel_factory_create_channel(
+        &exec_ctx, &client_channel_factory, target,
+        GRPC_CLIENT_CHANNEL_TYPE_REGULAR, new_args);
+    // Clean up.
+    grpc_channel_args_destroy(&exec_ctx, new_args);
     grpc_exec_ctx_finish(&exec_ctx);
-    return grpc_lame_client_channel_create(
-        target, GRPC_STATUS_INTERNAL,
-        "Security connector exists in channel args.");
-  }
-  // Create security connector and construct new channel args.
-  grpc_channel_security_connector *security_connector;
-  grpc_channel_args *new_args_from_connector;
-  if (grpc_channel_credentials_create_security_connector(
-          &exec_ctx, creds, target, args, &security_connector,
-          &new_args_from_connector) != GRPC_SECURITY_OK) {
-    grpc_exec_ctx_finish(&exec_ctx);
-    return grpc_lame_client_channel_create(
-        target, GRPC_STATUS_INTERNAL, "Failed to create security connector.");
-  }
-  // Add channel args containing the client channel factory and security
-  // connector.
-  grpc_arg args_to_add[2];
-  args_to_add[0] =
-      grpc_client_channel_factory_create_channel_arg(&client_channel_factory);
-  args_to_add[1] = grpc_security_connector_to_arg(&security_connector->base);
-  grpc_channel_args *new_args = grpc_channel_args_copy_and_add(
-      new_args_from_connector != NULL ? new_args_from_connector : args,
-      args_to_add, GPR_ARRAY_SIZE(args_to_add));
-  if (new_args_from_connector != NULL) {
-    grpc_channel_args_destroy(&exec_ctx, new_args_from_connector);
   }
-  // Create channel.
-  grpc_channel *channel = client_channel_factory_create_channel(
-      &exec_ctx, &client_channel_factory, target,
-      GRPC_CLIENT_CHANNEL_TYPE_REGULAR, new_args);
-  // Clean up.
-  GRPC_SECURITY_CONNECTOR_UNREF(&exec_ctx, &security_connector->base,
-                                "secure_client_channel_factory_create_channel");
-  grpc_channel_args_destroy(&exec_ctx, new_args);
-  grpc_exec_ctx_finish(&exec_ctx);
-  return channel; /* may be NULL */
+  return channel != NULL ? channel
+                         : grpc_lame_client_channel_create(
+                               target, GRPC_STATUS_INTERNAL,
+                               "Failed to create secure client channel");
 }

src/core/ext/transport/chttp2/transport/chttp2_transport.c

@@ -124,6 +124,21 @@ static void close_transport_locked(grpc_exec_ctx *exec_ctx,
 static void end_all_the_calls(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                               grpc_error *error);
 
+static void start_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                  grpc_error *error);
+static void finish_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                   grpc_error *error);
+
+static void cancel_pings(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                         grpc_error *error);
+static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                             grpc_chttp2_ping_type ping_type,
+                             grpc_closure *on_initiate,
+                             grpc_closure *on_complete);
+
+#define DEFAULT_MIN_TIME_BETWEEN_PINGS_MS 0
+#define DEFAULT_MAX_PINGS_BETWEEN_DATA 3
+
 /*******************************************************************************
  * CONSTRUCTION/DESTRUCTION/REFCOUNTING
  */
@@ -153,18 +168,9 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
   grpc_chttp2_stream_map_destroy(&t->stream_map);
   grpc_connectivity_state_destroy(exec_ctx, &t->channel_callback.state_tracker);
 
-  grpc_combiner_destroy(exec_ctx, t->combiner);
+  GRPC_COMBINER_UNREF(exec_ctx, t->combiner, "chttp2_transport");
 
-  /* callback remaining pings: they're not allowed to call into the transpot,
-     and maybe they hold resources that need to be freed */
-  while (t->pings.next != &t->pings) {
-    grpc_chttp2_outstanding_ping *ping = t->pings.next;
-    grpc_closure_sched(exec_ctx, ping->on_recv,
-                       GRPC_ERROR_CREATE("Transport closed"));
-    ping->next->prev = ping->prev;
-    ping->prev->next = ping->next;
-    gpr_free(ping);
-  }
+  cancel_pings(exec_ctx, t, GRPC_ERROR_CREATE("Transport destroyed"));
 
   while (t->write_cb_pool) {
     grpc_chttp2_write_cb *next = t->write_cb_pool->next;
@@ -172,6 +178,7 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
     t->write_cb_pool = next;
   }
 
+  gpr_free(t->ping_acks);
   gpr_free(t->peer_string);
   gpr_free(t);
 }
@@ -224,10 +231,6 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   t->is_client = is_client;
   t->outgoing_window = DEFAULT_WINDOW;
   t->incoming_window = DEFAULT_WINDOW;
-  t->stream_lookahead = DEFAULT_WINDOW;
-  t->connection_window_target = DEFAULT_CONNECTION_WINDOW_TARGET;
-  t->ping_counter = 1;
-  t->pings.next = t->pings.prev = &t->pings;
   t->deframe_state = is_client ? GRPC_DTS_FH_0 : GRPC_DTS_CLIENT_PREFIX_0;
   t->is_first_frame = true;
   grpc_connectivity_state_init(
@@ -248,6 +251,22 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   grpc_closure_init(&t->destructive_reclaimer_locked,
                     destructive_reclaimer_locked, t,
                     grpc_combiner_scheduler(t->combiner, false));
+  grpc_closure_init(&t->start_bdp_ping_locked, start_bdp_ping_locked, t,
+                    grpc_combiner_scheduler(t->combiner, false));
+  grpc_closure_init(&t->finish_bdp_ping_locked, finish_bdp_ping_locked, t,
+                    grpc_combiner_scheduler(t->combiner, false));
+
+  grpc_bdp_estimator_init(&t->bdp_estimator, t->peer_string);
+  t->last_pid_update = gpr_now(GPR_CLOCK_MONOTONIC);
+  grpc_pid_controller_init(
+      &t->pid_controller,
+      (grpc_pid_controller_args){.gain_p = 4,
+                                 .gain_i = 8,
+                                 .gain_d = 0,
+                                 .initial_control_value = log2(DEFAULT_WINDOW),
+                                 .min_control_value = -1,
+                                 .max_control_value = 22,
+                                 .integral_range = 10});
 
   grpc_chttp2_goaway_parser_init(&t->goaway_parser);
   grpc_chttp2_hpack_parser_init(exec_ctx, &t->hpack_parser);
@@ -273,6 +292,7 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   t->force_send_settings = 1 << GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE;
   t->sent_local_settings = 0;
   t->write_buffer_size = DEFAULT_WINDOW;
+  t->enable_bdp_probe = true;
 
   if (is_client) {
     grpc_slice_buffer_add(&t->outbuf, grpc_slice_from_copied_string(
@@ -290,6 +310,12 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
                DEFAULT_MAX_HEADER_LIST_SIZE);
 
+  t->ping_policy = (grpc_chttp2_repeated_ping_policy){
+      .max_pings_without_data = DEFAULT_MAX_PINGS_BETWEEN_DATA,
+      .min_time_between_pings =
+          gpr_time_from_millis(DEFAULT_MIN_TIME_BETWEEN_PINGS_MS, GPR_TIMESPAN),
+  };
+
   if (channel_args) {
     for (i = 0; i < channel_args->num_args; i++) {
       if (0 == strcmp(channel_args->args[i].key,
@@ -306,14 +332,6 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
             t->next_stream_id = (uint32_t)value;
           }
         }
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES)) {
-        const grpc_integer_options options = {-1, 5, INT_MAX};
-        const int value =
-            grpc_channel_arg_get_integer(&channel_args->args[i], options);
-        if (value >= 0) {
-          t->stream_lookahead = (uint32_t)value;
-        }
       } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER)) {
         const grpc_integer_options options = {-1, 0, INT_MAX};
@@ -323,35 +341,54 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
           grpc_chttp2_hpack_compressor_set_max_usable_size(&t->hpack_compressor,
                                                            (uint32_t)value);
         }
+      } else if (0 == strcmp(channel_args->args[i].key,
+                             GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA)) {
+        t->ping_policy.max_pings_without_data = grpc_channel_arg_get_integer(
+            &channel_args->args[i],
+            (grpc_integer_options){DEFAULT_MAX_PINGS_BETWEEN_DATA, 0, INT_MAX});
+      } else if (0 == strcmp(channel_args->args[i].key,
+                             GRPC_ARG_HTTP2_MIN_TIME_BETWEEN_PINGS_MS)) {
+        t->ping_policy.min_time_between_pings = gpr_time_from_millis(
+            grpc_channel_arg_get_integer(
+                &channel_args->args[i],
+                (grpc_integer_options){DEFAULT_MIN_TIME_BETWEEN_PINGS_MS, 0,
+                                       INT_MAX}),
+            GPR_TIMESPAN);
       } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_WRITE_BUFFER_SIZE)) {
         t->write_buffer_size = (uint32_t)grpc_channel_arg_get_integer(
             &channel_args->args[i],
             (grpc_integer_options){0, 0, MAX_WRITE_BUFFER_SIZE});
+      } else if (0 ==
+                 strcmp(channel_args->args[i].key, GRPC_ARG_HTTP2_BDP_PROBE)) {
+        t->enable_bdp_probe = grpc_channel_arg_get_integer(
+            &channel_args->args[i], (grpc_integer_options){1, 0, 1});
       } else {
         static const struct {
           const char *channel_arg_name;
           grpc_chttp2_setting_id setting_id;
           grpc_integer_options integer_options;
           bool availability[2] /* server, client */;
-        } settings_map[] = {
-            {GRPC_ARG_MAX_CONCURRENT_STREAMS,
-             GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
-             {-1, 0, INT_MAX},
-             {true, false}},
-            {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
-             GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
-             {-1, 0, INT_MAX},
-             {true, true}},
-            {GRPC_ARG_MAX_METADATA_SIZE,
-             GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
-             {-1, 0, INT_MAX},
-             {true, true}},
-            {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
-             GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
-             {-1, 16384, 16777215},
-             {true, true}},
-        };
+        } settings_map[] = {{GRPC_ARG_MAX_CONCURRENT_STREAMS,
+                             GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
+                             {-1, 0, INT32_MAX},
+                             {true, false}},
+                            {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
+                             GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
+                             {-1, 0, INT32_MAX},
+                             {true, true}},
+                            {GRPC_ARG_MAX_METADATA_SIZE,
+                             GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
+                             {-1, 0, INT32_MAX},
+                             {true, true}},
+                            {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
+                             GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
+                             {-1, 16384, 16777215},
+                             {true, true}},
+                            {GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES,
+                             GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
+                             {-1, 5, INT32_MAX},
+                             {true, true}}};
         for (j = 0; j < (int)GPR_ARRAY_SIZE(settings_map); j++) {
           if (0 == strcmp(channel_args->args[i].key,
                           settings_map[j].channel_arg_name)) {
@@ -374,6 +411,9 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     }
   }
 
+  t->ping_state.pings_before_data_required =
+      t->ping_policy.max_pings_without_data;
+
   grpc_chttp2_initiate_write(exec_ctx, t, false, "init");
   post_benign_reclaimer(exec_ctx, t);
 }
@@ -425,6 +465,7 @@ static void close_transport_locked(grpc_exec_ctx *exec_ctx,
       GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "chttp2_writing:close");
     }
     end_all_the_calls(exec_ctx, t, GRPC_ERROR_REF(error));
+    cancel_pings(exec_ctx, t, GRPC_ERROR_REF(error));
   }
   GRPC_ERROR_UNREF(error);
 }
@@ -475,11 +516,6 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
 
   if (server_data) {
     s->id = (uint32_t)(uintptr_t)server_data;
-    s->outgoing_window = t->settings[GRPC_PEER_SETTINGS]
-                                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    s->incoming_window = s->max_recv_bytes =
-        t->settings[GRPC_SENT_SETTINGS]
-                   [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
     *t->accepting_stream = s;
     grpc_chttp2_stream_map_add(&t->stream_map, s->id, s);
     post_destructive_reclaimer(exec_ctx, t);
@@ -508,6 +544,7 @@ static void destroy_stream_locked(grpc_exec_ctx *exec_ctx, void *sp,
   }
 
   grpc_chttp2_list_remove_stalled_by_transport(t, s);
+  grpc_chttp2_list_remove_stalled_by_stream(t, s);
 
   for (int i = 0; i < STREAM_LIST_COUNT; i++) {
     if (s->included[i]) {
@@ -647,13 +684,21 @@ void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_END("grpc_chttp2_initiate_write", 0);
 }
 
-void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
-                                 grpc_chttp2_transport *t,
-                                 grpc_chttp2_stream *s, bool covered_by_poller,
-                                 const char *reason) {
+void grpc_chttp2_become_writable(
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t, grpc_chttp2_stream *s,
+    grpc_chttp2_stream_write_type stream_write_type, const char *reason) {
   if (!t->closed && grpc_chttp2_list_add_writable_stream(t, s)) {
     GRPC_CHTTP2_STREAM_REF(s, "chttp2_writing:become");
-    grpc_chttp2_initiate_write(exec_ctx, t, covered_by_poller, reason);
+  }
+  switch (stream_write_type) {
+    case GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK:
+      break;
+    case GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED:
+      grpc_chttp2_initiate_write(exec_ctx, t, true, reason);
+      break;
+    case GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED:
+      grpc_chttp2_initiate_write(exec_ctx, t, false, reason);
+      break;
   }
 }
 
@@ -781,7 +826,6 @@ void grpc_chttp2_add_incoming_goaway(grpc_exec_ctx *exec_ctx,
 static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
                                      grpc_chttp2_transport *t) {
   grpc_chttp2_stream *s;
-  uint32_t stream_incoming_window;
   /* start streams where we have free grpc_chttp2_stream ids and free
    * concurrency */
   while (t->next_stream_id <= MAX_CLIENT_STREAM_ID &&
@@ -804,15 +848,11 @@ static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
                              "no_more_stream_ids");
     }
 
-    s->outgoing_window = t->settings[GRPC_PEER_SETTINGS]
-                                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    s->incoming_window = stream_incoming_window =
-        t->settings[GRPC_SENT_SETTINGS]
-                   [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    s->max_recv_bytes = GPR_MAX(stream_incoming_window, s->max_recv_bytes);
     grpc_chttp2_stream_map_add(&t->stream_map, s->id, s);
     post_destructive_reclaimer(exec_ctx, t);
-    grpc_chttp2_become_writable(exec_ctx, t, s, true, "new_stream");
+    grpc_chttp2_become_writable(exec_ctx, t, s,
+                                GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+                                "new_stream");
   }
   /* cancel out streams that will never be started */
   while (t->next_stream_id >= MAX_CLIENT_STREAM_ID &&
@@ -907,7 +947,9 @@ static void maybe_become_writable_due_to_send_msg(grpc_exec_ctx *exec_ctx,
                                                   grpc_chttp2_stream *s) {
   if (s->id != 0 && (!s->write_buffering ||
                      s->flow_controlled_buffer.length > t->write_buffer_size)) {
-    grpc_chttp2_become_writable(exec_ctx, t, s, true, "op.send_message");
+    grpc_chttp2_become_writable(exec_ctx, t, s,
+                                GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+                                "op.send_message");
   }
 }
 
@@ -1069,7 +1111,8 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
           }
         } else {
           GPR_ASSERT(s->id != 0);
-          grpc_chttp2_become_writable(exec_ctx, t, s, true,
+          grpc_chttp2_become_writable(exec_ctx, t, s,
+                                      GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
                                       "op.send_initial_metadata");
         }
       } else {
@@ -1160,7 +1203,8 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
       } else if (s->id != 0) {
         /* TODO(ctiller): check if there's flow control for any outstanding
            bytes before going writable */
-        grpc_chttp2_become_writable(exec_ctx, t, s, true,
+        grpc_chttp2_become_writable(exec_ctx, t, s,
+                                    GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
                                     "op.send_trailing_metadata");
       }
     }
@@ -1179,8 +1223,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
     s->recv_message = op->recv_message;
     if (s->id != 0 &&
         (s->incoming_frames.head == NULL || s->incoming_frames.head->is_tail)) {
-      incoming_byte_stream_update_flow_control(exec_ctx, t, s,
-                                               t->stream_lookahead, 0);
+      incoming_byte_stream_update_flow_control(exec_ctx, t, s, 5, 0);
     }
     grpc_chttp2_maybe_complete_recv_message(exec_ctx, t, s);
   }
@@ -1224,43 +1267,46 @@ static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   GPR_TIMER_END("perform_stream_op", 0);
 }
 
+static void cancel_pings(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                         grpc_error *error) {
+  /* callback remaining pings: they're not allowed to call into the transpot,
+     and maybe they hold resources that need to be freed */
+  for (size_t i = 0; i < GRPC_CHTTP2_PING_TYPE_COUNT; i++) {
+    grpc_chttp2_ping_queue *pq = &t->ping_queues[i];
+    for (size_t j = 0; j < GRPC_CHTTP2_PCL_COUNT; j++) {
+      grpc_closure_list_fail_all(&pq->lists[j], GRPC_ERROR_REF(error));
+      grpc_closure_list_sched(exec_ctx, &pq->lists[j]);
+    }
+  }
+  GRPC_ERROR_UNREF(error);
+}
+
 static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                             grpc_closure *on_recv) {
-  grpc_chttp2_outstanding_ping *p = gpr_malloc(sizeof(*p));
-  p->next = &t->pings;
-  p->prev = p->next->prev;
-  p->prev->next = p->next->prev = p;
-  p->id[0] = (uint8_t)((t->ping_counter >> 56) & 0xff);
-  p->id[1] = (uint8_t)((t->ping_counter >> 48) & 0xff);
-  p->id[2] = (uint8_t)((t->ping_counter >> 40) & 0xff);
-  p->id[3] = (uint8_t)((t->ping_counter >> 32) & 0xff);
-  p->id[4] = (uint8_t)((t->ping_counter >> 24) & 0xff);
-  p->id[5] = (uint8_t)((t->ping_counter >> 16) & 0xff);
-  p->id[6] = (uint8_t)((t->ping_counter >> 8) & 0xff);
-  p->id[7] = (uint8_t)(t->ping_counter & 0xff);
-  t->ping_counter++;
-  p->on_recv = on_recv;
-  grpc_slice_buffer_add(&t->qbuf, grpc_chttp2_ping_create(0, p->id));
-  grpc_chttp2_initiate_write(exec_ctx, t, true, "send_ping");
+                             grpc_chttp2_ping_type ping_type,
+                             grpc_closure *on_initiate, grpc_closure *on_ack) {
+  grpc_chttp2_ping_queue *pq = &t->ping_queues[ping_type];
+  grpc_closure_list_append(&pq->lists[GRPC_CHTTP2_PCL_INITIATE], on_initiate,
+                           GRPC_ERROR_NONE);
+  if (grpc_closure_list_append(&pq->lists[GRPC_CHTTP2_PCL_NEXT], on_ack,
+                               GRPC_ERROR_NONE)) {
+    grpc_chttp2_initiate_write(exec_ctx, t, false, "send_ping");
+  }
 }
 
 void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                          const uint8_t *opaque_8bytes) {
-  grpc_chttp2_outstanding_ping *ping;
-  for (ping = t->pings.next; ping != &t->pings; ping = ping->next) {
-    if (0 == memcmp(opaque_8bytes, ping->id, 8)) {
-      grpc_closure_sched(exec_ctx, ping->on_recv, GRPC_ERROR_NONE);
-      ping->next->prev = ping->prev;
-      ping->prev->next = ping->next;
-      gpr_free(ping);
-      return;
-    }
+                          uint64_t id) {
+  grpc_chttp2_ping_queue *pq =
+      &t->ping_queues[id % GRPC_CHTTP2_PING_TYPE_COUNT];
+  if (pq->inflight_id != id) {
+    char *from = grpc_endpoint_get_peer(t->ep);
+    gpr_log(GPR_DEBUG, "Unknown ping response from %s: %" PRIx64, from, id);
+    gpr_free(from);
+    return;
+  }
+  grpc_closure_list_sched(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
+  if (!grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_NEXT])) {
+    grpc_chttp2_initiate_write(exec_ctx, t, false, "continue_pings");
   }
-  char *msg = gpr_dump((const char *)opaque_8bytes, 8, GPR_DUMP_HEX);
-  char *from = grpc_endpoint_get_peer(t->ep);
-  gpr_log(GPR_DEBUG, "Unknown ping response from %s: %s", from, msg);
-  gpr_free(from);
-  gpr_free(msg);
 }
 
 static void send_goaway(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
@@ -1308,7 +1354,8 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
   }
 
   if (op->send_ping) {
-    send_ping_locked(exec_ctx, t, op->send_ping);
+    send_ping_locked(exec_ctx, t, GRPC_CHTTP2_PING_ON_NEXT_WRITE, NULL,
+                     op->send_ping);
   }
 
   if (close_transport != GRPC_ERROR_NONE) {
@@ -1733,34 +1780,28 @@ static void end_all_the_calls(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   GRPC_ERROR_UNREF(error);
 }
 
-/** update window from a settings change */
-typedef struct {
-  grpc_chttp2_transport *t;
-  grpc_exec_ctx *exec_ctx;
-} update_global_window_args;
+/*******************************************************************************
+ * INPUT PROCESSING - PARSING
+ */
 
-static void update_global_window(void *args, uint32_t id, void *stream) {
-  update_global_window_args *a = args;
-  grpc_chttp2_transport *t = a->t;
-  grpc_chttp2_stream *s = stream;
-  int was_zero;
-  int is_zero;
-  int64_t initial_window_update = t->initial_window_update;
-
-  if (initial_window_update > 0) {
-    was_zero = s->outgoing_window <= 0;
-    GRPC_CHTTP2_FLOW_CREDIT_STREAM("settings", t, s, outgoing_window,
-                                   initial_window_update);
-    is_zero = s->outgoing_window <= 0;
-
-    if (was_zero && !is_zero) {
-      grpc_chttp2_become_writable(a->exec_ctx, t, s, true,
-                                  "update_global_window");
-    }
+static void update_bdp(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                       double bdp_dbl) {
+  uint32_t bdp;
+  if (bdp_dbl <= 0) {
+    bdp = 0;
+  } else if (bdp_dbl > UINT32_MAX) {
+    bdp = UINT32_MAX;
   } else {
-    GRPC_CHTTP2_FLOW_DEBIT_STREAM("settings", t, s, outgoing_window,
-                                  -initial_window_update);
+    bdp = (uint32_t)(bdp_dbl);
+  }
+  int64_t delta =
+      (int64_t)bdp -
+      (int64_t)t->settings[GRPC_LOCAL_SETTINGS]
+                          [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
+  if (delta == 0 || (bdp != 0 && delta > -1024 && delta < 1024)) {
+    return;
   }
+  push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE, bdp);
 }
 
 /*******************************************************************************
@@ -1802,6 +1843,7 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
   GPR_TIMER_BEGIN("reading_action_locked", 0);
 
   grpc_chttp2_transport *t = tp;
+  bool need_bdp_ping = false;
 
   GRPC_ERROR_REF(error);
 
@@ -1819,9 +1861,14 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
     grpc_error *errors[3] = {GRPC_ERROR_REF(error), GRPC_ERROR_NONE,
                              GRPC_ERROR_NONE};
     for (; i < t->read_buffer.count && errors[1] == GRPC_ERROR_NONE; i++) {
+      if (grpc_bdp_estimator_add_incoming_bytes(
+              &t->bdp_estimator,
+              (int64_t)GRPC_SLICE_LENGTH(t->read_buffer.slices[i]))) {
+        need_bdp_ping = true;
+      }
       errors[1] =
           grpc_chttp2_perform_read(exec_ctx, t, t->read_buffer.slices[i]);
-    };
+    }
     if (errors[1] != GRPC_ERROR_NONE) {
       errors[2] = try_http_parsing(exec_ctx, t);
       GRPC_ERROR_UNREF(error);
@@ -1835,21 +1882,16 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
 
     GPR_TIMER_BEGIN("post_parse_locked", 0);
     if (t->initial_window_update != 0) {
-      update_global_window_args args = {t, exec_ctx};
-      grpc_chttp2_stream_map_for_each(&t->stream_map, update_global_window,
-                                      &args);
+      if (t->initial_window_update > 0) {
+        grpc_chttp2_stream *s;
+        while (grpc_chttp2_list_pop_stalled_by_stream(t, &s)) {
+          grpc_chttp2_become_writable(
+              exec_ctx, t, s, GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
+              "unstalled");
+        }
+      }
       t->initial_window_update = 0;
     }
-    /* handle higher level things */
-    if (t->incoming_window < t->connection_window_target * 3 / 4) {
-      int64_t announce_bytes = t->connection_window_target - t->incoming_window;
-      GRPC_CHTTP2_FLOW_CREDIT_TRANSPORT("parsed", t, announce_incoming_window,
-                                        announce_bytes);
-      GRPC_CHTTP2_FLOW_CREDIT_TRANSPORT("parsed", t, incoming_window,
-                                        announce_bytes);
-      grpc_chttp2_initiate_write(exec_ctx, t, false, "global incoming window");
-    }
-
     GPR_TIMER_END("post_parse_locked", 0);
   }
 
@@ -1870,6 +1912,38 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
   if (keep_reading) {
     grpc_endpoint_read(exec_ctx, t->ep, &t->read_buffer,
                        &t->read_action_locked);
+
+    if (t->enable_bdp_probe) {
+      if (need_bdp_ping) {
+        GRPC_CHTTP2_REF_TRANSPORT(t, "bdp_ping");
+        grpc_bdp_estimator_schedule_ping(&t->bdp_estimator);
+        send_ping_locked(exec_ctx, t,
+                         GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE,
+                         &t->start_bdp_ping_locked, &t->finish_bdp_ping_locked);
+      }
+
+      int64_t estimate = -1;
+      if (grpc_bdp_estimator_get_estimate(&t->bdp_estimator, &estimate)) {
+        double target = 1 + log2((double)estimate);
+        double memory_pressure = grpc_resource_quota_get_memory_pressure(
+            grpc_resource_user_quota(grpc_endpoint_get_resource_user(t->ep)));
+        if (memory_pressure > 0.8) {
+          target *= 1 - GPR_MIN(1, (memory_pressure - 0.8) / 0.1);
+        }
+        double bdp_error =
+            target - grpc_pid_controller_last(&t->pid_controller);
+        gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+        gpr_timespec dt_timespec = gpr_time_sub(now, t->last_pid_update);
+        double dt = (double)dt_timespec.tv_sec + dt_timespec.tv_nsec * 1e-9;
+        if (dt > 0.1) {
+          dt = 0.1;
+        }
+        double log2_bdp_guess =
+            grpc_pid_controller_update(&t->pid_controller, bdp_error, dt);
+        update_bdp(exec_ctx, t, pow(2, log2_bdp_guess));
+        t->last_pid_update = now;
+      }
+    }
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "keep_reading");
   } else {
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "reading_action");
@@ -1882,6 +1956,26 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
   GPR_TIMER_END("reading_action_locked", 0);
 }
 
+static void start_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                  grpc_error *error) {
+  grpc_chttp2_transport *t = tp;
+  if (grpc_http_trace) {
+    gpr_log(GPR_DEBUG, "%s: Start BDP ping", t->peer_string);
+  }
+  grpc_bdp_estimator_start_ping(&t->bdp_estimator);
+}
+
+static void finish_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                   grpc_error *error) {
+  grpc_chttp2_transport *t = tp;
+  if (grpc_http_trace) {
+    gpr_log(GPR_DEBUG, "%s: Complete BDP ping", t->peer_string);
+  }
+  grpc_bdp_estimator_complete_ping(&t->bdp_estimator);
+
+  GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "bdp_ping");
+}
+
 /*******************************************************************************
  * CALLBACK LOOP
  */
@@ -1932,10 +2026,12 @@ static void incoming_byte_stream_update_flow_control(grpc_exec_ctx *exec_ctx,
                                                      size_t max_size_hint,
                                                      size_t have_already) {
   uint32_t max_recv_bytes;
+  uint32_t initial_window_size =
+      t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
 
   /* clamp max recv hint to an allowable size */
-  if (max_size_hint >= UINT32_MAX - t->stream_lookahead) {
-    max_recv_bytes = UINT32_MAX - t->stream_lookahead;
+  if (max_size_hint >= UINT32_MAX - initial_window_size) {
+    max_recv_bytes = UINT32_MAX - initial_window_size;
   } else {
     max_recv_bytes = (uint32_t)max_size_hint;
   }
@@ -1948,20 +2044,26 @@ static void incoming_byte_stream_update_flow_control(grpc_exec_ctx *exec_ctx,
   }
 
   /* add some small lookahead to keep pipelines flowing */
-  GPR_ASSERT(max_recv_bytes <= UINT32_MAX - t->stream_lookahead);
-  max_recv_bytes += t->stream_lookahead;
-  if (s->max_recv_bytes < max_recv_bytes) {
-    uint32_t add_max_recv_bytes = max_recv_bytes - s->max_recv_bytes;
-    bool new_window_write_is_covered_by_poller =
-        s->max_recv_bytes < have_already;
-    GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, max_recv_bytes,
-                                   add_max_recv_bytes);
-    GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, incoming_window,
+  GPR_ASSERT(max_recv_bytes <= UINT32_MAX - initial_window_size);
+  if (s->incoming_window_delta < max_recv_bytes && !s->read_closed) {
+    uint32_t add_max_recv_bytes =
+        (uint32_t)(max_recv_bytes - s->incoming_window_delta);
+    grpc_chttp2_stream_write_type write_type =
+        GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED;
+    if (s->incoming_window_delta + initial_window_size <
+        (int64_t)have_already) {
+      write_type = GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED;
+    }
+    GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, incoming_window_delta,
                                    add_max_recv_bytes);
     GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, announce_window,
                                    add_max_recv_bytes);
-    grpc_chttp2_become_writable(exec_ctx, t, s,
-                                new_window_write_is_covered_by_poller,
+    if ((int64_t)s->incoming_window_delta + (int64_t)initial_window_size -
+            (int64_t)s->announce_window >
+        (int64_t)initial_window_size / 2) {
+      write_type = GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK;
+    }
+    grpc_chttp2_become_writable(exec_ctx, t, s, write_type,
                                 "read_incoming_stream");
   }
 }

src/core/ext/transport/chttp2/transport/frame_ping.c

@@ -40,7 +40,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint8_t *opaque_8bytes) {
+grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint64_t opaque_8bytes) {
   grpc_slice slice = grpc_slice_malloc(9 + 8);
   uint8_t *p = GRPC_SLICE_START_PTR(slice);
 
@@ -53,7 +53,14 @@ grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint8_t *opaque_8bytes) {
   *p++ = 0;
   *p++ = 0;
   *p++ = 0;
-  memcpy(p, opaque_8bytes, 8);
+  *p++ = (uint8_t)(opaque_8bytes >> 56);
+  *p++ = (uint8_t)(opaque_8bytes >> 48);
+  *p++ = (uint8_t)(opaque_8bytes >> 40);
+  *p++ = (uint8_t)(opaque_8bytes >> 32);
+  *p++ = (uint8_t)(opaque_8bytes >> 24);
+  *p++ = (uint8_t)(opaque_8bytes >> 16);
+  *p++ = (uint8_t)(opaque_8bytes >> 8);
+  *p++ = (uint8_t)(opaque_8bytes);
 
   return slice;
 }
@@ -70,6 +77,7 @@ grpc_error *grpc_chttp2_ping_parser_begin_frame(grpc_chttp2_ping_parser *parser,
   }
   parser->byte = 0;
   parser->is_ack = flags;
+  parser->opaque_8bytes = 0;
   return GRPC_ERROR_NONE;
 }
 
@@ -83,7 +91,7 @@ grpc_error *grpc_chttp2_ping_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
   grpc_chttp2_ping_parser *p = parser;
 
   while (p->byte != 8 && cur != end) {
-    p->opaque_8bytes[p->byte] = *cur;
+    p->opaque_8bytes |= (((uint64_t)*cur) << (8 * p->byte));
     cur++;
     p->byte++;
   }
@@ -93,8 +101,12 @@ grpc_error *grpc_chttp2_ping_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
     if (p->is_ack) {
       grpc_chttp2_ack_ping(exec_ctx, t, p->opaque_8bytes);
     } else {
-      grpc_slice_buffer_add(&t->qbuf,
-                            grpc_chttp2_ping_create(1, p->opaque_8bytes));
+      if (t->ping_ack_count == t->ping_ack_capacity) {
+        t->ping_ack_capacity = GPR_MAX(t->ping_ack_capacity * 3 / 2, 3);
+        t->ping_acks = gpr_realloc(
+            t->ping_acks, t->ping_ack_capacity * sizeof(*t->ping_acks));
+      }
+      t->ping_acks[t->ping_ack_count++] = p->opaque_8bytes;
       grpc_chttp2_initiate_write(exec_ctx, t, false, "ping response");
     }
   }

src/core/ext/transport/chttp2/transport/frame_ping.h

@@ -41,10 +41,10 @@
 typedef struct {
   uint8_t byte;
   uint8_t is_ack;
-  uint8_t opaque_8bytes[8];
+  uint64_t opaque_8bytes;
 } grpc_chttp2_ping_parser;
 
-grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint8_t *opaque_8bytes);
+grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint64_t opaque_8bytes);
 
 grpc_error *grpc_chttp2_ping_parser_begin_frame(grpc_chttp2_ping_parser *parser,
                                                 uint32_t length, uint8_t flags);

src/core/ext/transport/chttp2/transport/frame_rst_stream.c

@@ -109,8 +109,13 @@ grpc_error *grpc_chttp2_rst_stream_parser_parse(grpc_exec_ctx *exec_ctx,
                       (((uint32_t)p->reason_bytes[3]));
     grpc_error *error = GRPC_ERROR_NONE;
     if (reason != GRPC_HTTP2_NO_ERROR || s->header_frames_received < 2) {
-      error = grpc_error_set_int(GRPC_ERROR_CREATE("RST_STREAM"),
-                                 GRPC_ERROR_INT_HTTP2_ERROR, (intptr_t)reason);
+      char *message;
+      gpr_asprintf(&message, "Received RST_STREAM with error code %d", reason);
+      error = grpc_error_set_int(
+          grpc_error_set_str(GRPC_ERROR_CREATE("RST_STREAM"),
+                             GRPC_ERROR_STR_GRPC_MESSAGE, message),
+          GRPC_ERROR_INT_HTTP2_ERROR, (intptr_t)reason);
+      gpr_free(message);
     }
     grpc_chttp2_mark_stream_closed(exec_ctx, t, s, true, true, error);
   }

src/core/ext/transport/chttp2/transport/frame_settings.c

@@ -236,7 +236,7 @@ grpc_error *grpc_chttp2_settings_parser_parse(grpc_exec_ctx *exec_ctx, void *p,
           }
           if (parser->id == GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE &&
               parser->incoming_settings[parser->id] != parser->value) {
-            t->initial_window_update =
+            t->initial_window_update +=
                 (int64_t)parser->value - parser->incoming_settings[parser->id];
             if (grpc_http_trace) {
               gpr_log(GPR_DEBUG, "adding %d for initial_window change",
@@ -245,8 +245,9 @@ grpc_error *grpc_chttp2_settings_parser_parse(grpc_exec_ctx *exec_ctx, void *p,
           }
           parser->incoming_settings[parser->id] = parser->value;
           if (grpc_http_trace) {
-            gpr_log(GPR_DEBUG, "CHTTP2:%s: got setting %d = %d",
-                    t->is_client ? "CLI" : "SVR", parser->id, parser->value);
+            gpr_log(GPR_DEBUG, "CHTTP2:%s:%s: got setting %d = %d",
+                    t->is_client ? "CLI" : "SVR", t->peer_string, parser->id,
+                    parser->value);
           }
         } else if (grpc_http_trace) {
           gpr_log(GPR_ERROR, "CHTTP2: Ignoring unknown setting %d (value %d)",

src/core/ext/transport/chttp2/transport/frame_window_update.c

@@ -110,13 +110,12 @@ grpc_error *grpc_chttp2_window_update_parser_parse(
 
     if (t->incoming_stream_id != 0) {
       if (s != NULL) {
-        bool was_zero = s->outgoing_window <= 0;
-        GRPC_CHTTP2_FLOW_CREDIT_STREAM("parse", t, s, outgoing_window,
+        GRPC_CHTTP2_FLOW_CREDIT_STREAM("parse", t, s, outgoing_window_delta,
                                        received_update);
-        bool is_zero = s->outgoing_window <= 0;
-        if (was_zero && !is_zero) {
-          grpc_chttp2_become_writable(exec_ctx, t, s, false,
-                                      "stream.read_flow_control");
+        if (grpc_chttp2_list_remove_stalled_by_stream(t, s)) {
+          grpc_chttp2_become_writable(
+              exec_ctx, t, s, GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
+              "stream.read_flow_control");
         }
       }
     } else {

src/core/ext/transport/chttp2/transport/internal.h

@@ -50,7 +50,9 @@
 #include "src/core/ext/transport/chttp2/transport/stream_map.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/transport/bdp_estimator.h"
 #include "src/core/lib/transport/connectivity_state.h"
+#include "src/core/lib/transport/pid_controller.h"
 #include "src/core/lib/transport/transport_impl.h"
 
 /* streams are kept in various linked lists depending on what things need to
@@ -59,6 +61,7 @@ typedef enum {
   GRPC_CHTTP2_LIST_WRITABLE,
   GRPC_CHTTP2_LIST_WRITING,
   GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT,
+  GRPC_CHTTP2_LIST_STALLED_BY_STREAM,
   /** streams that are waiting to start because there are too many concurrent
       streams on the connection */
   GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY,
@@ -72,6 +75,34 @@ typedef enum {
   GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER,
 } grpc_chttp2_write_state;
 
+typedef enum {
+  GRPC_CHTTP2_PING_ON_NEXT_WRITE = 0,
+  GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE,
+  GRPC_CHTTP2_PING_TYPE_COUNT /* must be last */
+} grpc_chttp2_ping_type;
+
+typedef enum {
+  GRPC_CHTTP2_PCL_INITIATE = 0,
+  GRPC_CHTTP2_PCL_NEXT,
+  GRPC_CHTTP2_PCL_INFLIGHT,
+  GRPC_CHTTP2_PCL_COUNT /* must be last */
+} grpc_chttp2_ping_closure_list;
+
+typedef struct {
+  grpc_closure_list lists[GRPC_CHTTP2_PCL_COUNT];
+  uint64_t inflight_id;
+} grpc_chttp2_ping_queue;
+
+typedef struct {
+  gpr_timespec min_time_between_pings;
+  int max_pings_without_data;
+} grpc_chttp2_repeated_ping_policy;
+
+typedef struct {
+  gpr_timespec last_ping_sent_time;
+  int pings_before_data_required;
+} grpc_chttp2_repeated_ping_state;
+
 /* deframer state for the overall http2 stream of bytes */
 typedef enum {
   /* prefix: one entry per http2 connection prefix byte */
@@ -144,14 +175,6 @@ typedef enum {
   GRPC_CHTTP2_GOAWAY_SENT,
 } grpc_chttp2_sent_goaway_state;
 
-/* Outstanding ping request data */
-typedef struct grpc_chttp2_outstanding_ping {
-  uint8_t id[8];
-  grpc_closure *on_recv;
-  struct grpc_chttp2_outstanding_ping *next;
-  struct grpc_chttp2_outstanding_ping *prev;
-} grpc_chttp2_outstanding_ping;
-
 typedef struct grpc_chttp2_write_cb {
   int64_t call_at_byte;
   grpc_closure *closure;
@@ -204,6 +227,9 @@ struct grpc_chttp2_transport {
   /** is there a read request to the endpoint outstanding? */
   uint8_t endpoint_reading;
 
+  /** should we probe bdp? */
+  bool enable_bdp_probe;
+
   /** various lists of streams */
   grpc_chttp2_stream_list lists[STREAM_LIST_COUNT];
 
@@ -271,16 +297,19 @@ struct grpc_chttp2_transport {
       copied to next_stream_id in parsing when parsing commences */
   uint32_t next_stream_id;
 
-  /** how far to lookahead in a stream? */
-  uint32_t stream_lookahead;
-
   /** last new stream id */
   uint32_t last_new_stream_id;
 
-  /** pings awaiting responses */
-  grpc_chttp2_outstanding_ping pings;
-  /** next payload for an outgoing ping */
-  uint64_t ping_counter;
+  /** ping queues for various ping insertion points */
+  grpc_chttp2_ping_queue ping_queues[GRPC_CHTTP2_PING_TYPE_COUNT];
+  grpc_chttp2_repeated_ping_policy ping_policy;
+  grpc_chttp2_repeated_ping_state ping_state;
+  uint64_t ping_ctr; /* unique id for pings */
+
+  /** ping acks */
+  size_t ping_ack_count;
+  size_t ping_ack_capacity;
+  uint64_t *ping_acks;
 
   /** parser for headers */
   grpc_chttp2_hpack_parser hpack_parser;
@@ -324,6 +353,13 @@ struct grpc_chttp2_transport {
 
   grpc_chttp2_write_cb *write_cb_pool;
 
+  /* bdp estimator */
+  grpc_bdp_estimator bdp_estimator;
+  grpc_pid_controller pid_controller;
+  grpc_closure start_bdp_ping_locked;
+  grpc_closure finish_bdp_ping_locked;
+  gpr_timespec last_pid_update;
+
   /* if non-NULL, close the transport with this error when writes are finished
    */
   grpc_error *close_transport_on_writes_finished;
@@ -362,12 +398,10 @@ struct grpc_chttp2_stream {
   /** HTTP2 stream id for this stream, or zero if one has not been assigned */
   uint32_t id;
 
-  /** window available for us to send to peer */
-  int64_t outgoing_window;
-  /** The number of bytes the upper layers have offered to receive.
-      As the upper layer offers more bytes, this value increases.
-      As bytes are read, this value decreases. */
-  uint32_t max_recv_bytes;
+  /** window available for us to send to peer, over or under the initial window
+    * size of the transport... ie:
+    * outgoing_window = outgoing_window_delta + transport.initial_window_size */
+  int64_t outgoing_window_delta;
   /** things the upper layers would like to send */
   grpc_metadata_batch *send_initial_metadata;
   grpc_closure *send_initial_metadata_finished;
@@ -428,8 +462,10 @@ struct grpc_chttp2_stream {
   grpc_error *forced_close_error;
   /** how many header frames have we received? */
   uint8_t header_frames_received;
-  /** window available for peer to send to us */
-  int64_t incoming_window;
+  /** window available for peer to send to us (as a delta on
+   * transport.initial_window_size)
+   * incoming_window = incoming_window_delta + transport.initial_window_size */
+  int64_t incoming_window_delta;
   /** parsing state for data frames */
   grpc_chttp2_data_parser data_parser;
   /** number of bytes received - reset at end of parse thread execution */
@@ -478,36 +514,43 @@ bool grpc_chttp2_list_add_writable_stream(grpc_chttp2_transport *t,
                                           grpc_chttp2_stream *s);
 /** Get a writable stream
     returns non-zero if there was a stream available */
-int grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
-                                         grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
+                                          grpc_chttp2_stream **s);
 bool grpc_chttp2_list_remove_writable_stream(
     grpc_chttp2_transport *t, grpc_chttp2_stream *s) GRPC_MUST_USE_RESULT;
 
 bool grpc_chttp2_list_add_writing_stream(grpc_chttp2_transport *t,
                                          grpc_chttp2_stream *s);
-int grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t);
-int grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
-                                        grpc_chttp2_stream **s);
+bool grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t);
+bool grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
+                                         grpc_chttp2_stream **s);
 
 void grpc_chttp2_list_add_written_stream(grpc_chttp2_transport *t,
                                          grpc_chttp2_stream *s);
-int grpc_chttp2_list_pop_written_stream(grpc_chttp2_transport *t,
-                                        grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_written_stream(grpc_chttp2_transport *t,
+                                         grpc_chttp2_stream **s);
 
 void grpc_chttp2_list_add_waiting_for_concurrency(grpc_chttp2_transport *t,
                                                   grpc_chttp2_stream *s);
-int grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
-                                                 grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
+                                                  grpc_chttp2_stream **s);
 void grpc_chttp2_list_remove_waiting_for_concurrency(grpc_chttp2_transport *t,
                                                      grpc_chttp2_stream *s);
 
 void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport *t,
                                                grpc_chttp2_stream *s);
-int grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
-                                              grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream **s);
 void grpc_chttp2_list_remove_stalled_by_transport(grpc_chttp2_transport *t,
                                                   grpc_chttp2_stream *s);
 
+void grpc_chttp2_list_add_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream *s);
+bool grpc_chttp2_list_pop_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream **s);
+bool grpc_chttp2_list_remove_stalled_by_stream(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream *s);
+
 grpc_chttp2_stream *grpc_chttp2_parsing_lookup_stream(grpc_chttp2_transport *t,
                                                       uint32_t id);
 grpc_chttp2_stream *grpc_chttp2_parsing_accept_stream(grpc_exec_ctx *exec_ctx,
@@ -672,13 +715,23 @@ void grpc_chttp2_incoming_byte_stream_finished(
     grpc_error *error);
 
 void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                          const uint8_t *opaque_8bytes);
+                          uint64_t id);
+
+typedef enum {
+  /* don't initiate a transport write, but piggyback on the next one */
+  GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK,
+  /* initiate a covered write */
+  GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+  /* initiate an uncovered write */
+  GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED
+} grpc_chttp2_stream_write_type;
 
 /** add a ref to the stream and add it to the writable list;
     ref will be dropped in writing.c */
 void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
                                  grpc_chttp2_transport *t,
-                                 grpc_chttp2_stream *s, bool covered_by_poller,
+                                 grpc_chttp2_stream *s,
+                                 grpc_chttp2_stream_write_type type,
                                  const char *reason);
 
 void grpc_chttp2_cancel_stream(grpc_exec_ctx *exec_ctx,

src/core/ext/transport/chttp2/transport/parsing.c

@@ -376,25 +376,45 @@ static grpc_error *update_incoming_window(grpc_exec_ctx *exec_ctx,
     return err;
   }
 
+  uint32_t target_incoming_window = GPR_MAX(
+      t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE],
+      1024);
   GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("parse", t, incoming_window,
                                    incoming_frame_size);
+  if (t->incoming_window <= target_incoming_window / 2) {
+    grpc_chttp2_initiate_write(exec_ctx, t, false, "flow_control");
+  }
 
   if (s != NULL) {
-    if (incoming_frame_size > s->incoming_window) {
+    if (incoming_frame_size >
+        s->incoming_window_delta +
+            t->settings[GRPC_ACKED_SETTINGS]
+                       [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE]) {
       char *msg;
       gpr_asprintf(&msg,
                    "frame of size %d overflows incoming window of %" PRId64,
-                   t->incoming_frame_size, s->incoming_window);
+                   t->incoming_frame_size,
+                   s->incoming_window_delta +
+                       t->settings[GRPC_ACKED_SETTINGS]
+                                  [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE]);
       grpc_error *err = GRPC_ERROR_CREATE(msg);
       gpr_free(msg);
       return err;
     }
 
-    GRPC_CHTTP2_FLOW_DEBIT_STREAM("parse", t, s, incoming_window,
+    GRPC_CHTTP2_FLOW_DEBIT_STREAM("parse", t, s, incoming_window_delta,
                                   incoming_frame_size);
+    if ((int64_t)t->settings[GRPC_SENT_SETTINGS]
+                            [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE] +
+            (int64_t)s->incoming_window_delta - (int64_t)s->announce_window <=
+        (int64_t)t->settings[GRPC_SENT_SETTINGS]
+                            [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE] /
+            2) {
+      grpc_chttp2_become_writable(exec_ctx, t, s,
+                                  GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
+                                  "window-update-required");
+    }
     s->received_bytes += incoming_frame_size;
-    s->max_recv_bytes -=
-        (uint32_t)GPR_MIN(s->max_recv_bytes, incoming_frame_size);
   }
 
   return GRPC_ERROR_NONE;

src/core/ext/transport/chttp2/transport/stream_lists.c

@@ -37,14 +37,14 @@
 
 /* core list management */
 
-static int stream_list_empty(grpc_chttp2_transport *t,
-                             grpc_chttp2_stream_list_id id) {
+static bool stream_list_empty(grpc_chttp2_transport *t,
+                              grpc_chttp2_stream_list_id id) {
   return t->lists[id].head == NULL;
 }
 
-static int stream_list_pop(grpc_chttp2_transport *t,
-                           grpc_chttp2_stream **stream,
-                           grpc_chttp2_stream_list_id id) {
+static bool stream_list_pop(grpc_chttp2_transport *t,
+                            grpc_chttp2_stream **stream,
+                            grpc_chttp2_stream_list_id id) {
   grpc_chttp2_stream *s = t->lists[id].head;
   if (s) {
     grpc_chttp2_stream *new_head = s->links[id].next;
@@ -124,8 +124,8 @@ bool grpc_chttp2_list_add_writable_stream(grpc_chttp2_transport *t,
   return stream_list_add(t, s, GRPC_CHTTP2_LIST_WRITABLE);
 }
 
-int grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
-                                         grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
+                                          grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_WRITABLE);
 }
 
@@ -139,12 +139,12 @@ bool grpc_chttp2_list_add_writing_stream(grpc_chttp2_transport *t,
   return stream_list_add(t, s, GRPC_CHTTP2_LIST_WRITING);
 }
 
-int grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t) {
+bool grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t) {
   return !stream_list_empty(t, GRPC_CHTTP2_LIST_WRITING);
 }
 
-int grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
-                                        grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
+                                         grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_WRITING);
 }
 
@@ -153,8 +153,8 @@ void grpc_chttp2_list_add_waiting_for_concurrency(grpc_chttp2_transport *t,
   stream_list_add(t, s, GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY);
 }
 
-int grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
-                                                 grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
+                                                  grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY);
 }
 
@@ -168,8 +168,8 @@ void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport *t,
   stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
 
-int grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
-                                              grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
 
@@ -177,3 +177,18 @@ void grpc_chttp2_list_remove_stalled_by_transport(grpc_chttp2_transport *t,
                                                   grpc_chttp2_stream *s) {
   stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
+
+void grpc_chttp2_list_add_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream *s) {
+  stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
+}
+
+bool grpc_chttp2_list_pop_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream **s) {
+  return stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
+}
+
+bool grpc_chttp2_list_remove_stalled_by_stream(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream *s) {
+  return stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
+}

src/core/ext/transport/chttp2/transport/writing.c

@@ -56,6 +56,75 @@ static void finish_write_cb(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   t->write_cb_pool = cb;
 }
 
+static void collapse_pings_from_into(grpc_chttp2_transport *t,
+                                     grpc_chttp2_ping_type ping_type,
+                                     grpc_chttp2_ping_queue *pq) {
+  for (size_t i = 0; i < GRPC_CHTTP2_PCL_COUNT; i++) {
+    grpc_closure_list_move(&t->ping_queues[ping_type].lists[i], &pq->lists[i]);
+  }
+}
+
+static void maybe_initiate_ping(grpc_exec_ctx *exec_ctx,
+                                grpc_chttp2_transport *t,
+                                grpc_chttp2_ping_type ping_type) {
+  grpc_chttp2_ping_queue *pq = &t->ping_queues[ping_type];
+  if (grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_NEXT])) {
+    /* no ping needed: wait */
+    return;
+  }
+  if (!grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_INFLIGHT])) {
+    /* ping already in-flight: wait */
+    if (grpc_http_trace || grpc_bdp_estimator_trace) {
+      gpr_log(GPR_DEBUG, "Ping delayed [%p]: already pinging", t->peer_string);
+    }
+    return;
+  }
+  if (t->ping_state.pings_before_data_required == 0 &&
+      t->ping_policy.max_pings_without_data != 0) {
+    /* need to send something of substance before sending a ping again */
+    if (grpc_http_trace || grpc_bdp_estimator_trace) {
+      gpr_log(GPR_DEBUG, "Ping delayed [%p]: too many recent pings: %d/%d",
+              t->peer_string, t->ping_state.pings_before_data_required,
+              t->ping_policy.max_pings_without_data);
+    }
+    return;
+  }
+  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+  gpr_timespec elapsed = gpr_time_sub(now, t->ping_state.last_ping_sent_time);
+  /*gpr_log(GPR_DEBUG, "elapsed:%d.%09d min:%d.%09d", (int)elapsed.tv_sec,
+          elapsed.tv_nsec, (int)t->ping_policy.min_time_between_pings.tv_sec,
+          (int)t->ping_policy.min_time_between_pings.tv_nsec);*/
+  if (gpr_time_cmp(elapsed, t->ping_policy.min_time_between_pings) < 0) {
+    /* not enough elapsed time between successive pings */
+    if (grpc_http_trace || grpc_bdp_estimator_trace) {
+      gpr_log(GPR_DEBUG,
+              "Ping delayed [%p]: not enough time elapsed since last ping",
+              t->peer_string);
+    }
+    return;
+  }
+  /* coalesce equivalent pings into this one */
+  switch (ping_type) {
+    case GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE:
+      collapse_pings_from_into(t, GRPC_CHTTP2_PING_ON_NEXT_WRITE, pq);
+      break;
+    case GRPC_CHTTP2_PING_ON_NEXT_WRITE:
+      break;
+    case GRPC_CHTTP2_PING_TYPE_COUNT:
+      GPR_UNREACHABLE_CODE(break);
+  }
+  pq->inflight_id = t->ping_ctr * GRPC_CHTTP2_PING_TYPE_COUNT + ping_type;
+  t->ping_ctr++;
+  grpc_closure_list_sched(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INITIATE]);
+  grpc_closure_list_move(&pq->lists[GRPC_CHTTP2_PCL_NEXT],
+                         &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
+  grpc_slice_buffer_add(&t->outbuf,
+                        grpc_chttp2_ping_create(false, pq->inflight_id));
+  t->ping_state.last_ping_sent_time = now;
+  t->ping_state.pings_before_data_required -=
+      (t->ping_state.pings_before_data_required != 0);
+}
+
 static void update_list(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                         grpc_chttp2_stream *s, int64_t send_bytes,
                         grpc_chttp2_write_cb **list, grpc_error *error) {
@@ -139,6 +208,8 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
       s->sent_initial_metadata = true;
       sent_initial_metadata = true;
       now_writing = true;
+      t->ping_state.pings_before_data_required =
+          t->ping_policy.max_pings_without_data;
     }
     /* send any window updates */
     if (s->announce_window > 0) {
@@ -146,15 +217,22 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
       grpc_slice_buffer_add(&t->outbuf,
                             grpc_chttp2_window_update_create(
                                 s->id, s->announce_window, &s->stats.outgoing));
+      t->ping_state.pings_before_data_required =
+          t->ping_policy.max_pings_without_data;
       GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, announce_window, announce);
     }
     if (sent_initial_metadata) {
       /* send any body bytes, if allowed by flow control */
       if (s->flow_controlled_buffer.length > 0) {
-        uint32_t max_outgoing =
-            (uint32_t)GPR_MIN(t->settings[GRPC_ACKED_SETTINGS]
-                                         [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
-                              GPR_MIN(s->outgoing_window, t->outgoing_window));
+        uint32_t stream_outgoing_window = (uint32_t)GPR_MAX(
+            0,
+            s->outgoing_window_delta +
+                (int64_t)t->settings[GRPC_PEER_SETTINGS]
+                                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE]);
+        uint32_t max_outgoing = (uint32_t)GPR_MIN(
+            t->settings[GRPC_ACKED_SETTINGS]
+                       [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+            GPR_MIN(stream_outgoing_window, t->outgoing_window));
         if (max_outgoing > 0) {
           uint32_t send_bytes =
               (uint32_t)GPR_MIN(max_outgoing, s->flow_controlled_buffer.length);
@@ -167,10 +245,12 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
           grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, send_bytes,
                                   is_last_frame, &s->stats.outgoing,
                                   &t->outbuf);
-          GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, outgoing_window,
+          GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, outgoing_window_delta,
                                         send_bytes);
           GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("write", t, outgoing_window,
                                            send_bytes);
+          t->ping_state.pings_before_data_required =
+              t->ping_policy.max_pings_without_data;
           if (is_last_frame) {
             s->send_trailing_metadata = NULL;
             s->sent_trailing_metadata = true;
@@ -189,6 +269,9 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
         } else if (t->outgoing_window == 0) {
           grpc_chttp2_list_add_stalled_by_transport(t, s);
           now_writing = true;
+        } else if (stream_outgoing_window == 0) {
+          grpc_chttp2_list_add_stalled_by_stream(t, s);
+          now_writing = true;
         }
       }
       if (s->send_trailing_metadata != NULL &&
@@ -227,15 +310,32 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
 
   /* if the grpc_chttp2_transport is ready to send a window update, do so here
      also; 3/4 is a magic number that will likely get tuned soon */
-  if (t->announce_incoming_window > 0) {
-    uint32_t announced =
-        (uint32_t)GPR_MIN(t->announce_incoming_window, UINT32_MAX);
-    GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("write", t, announce_incoming_window,
-                                     announced);
+  uint32_t target_incoming_window = GPR_MAX(
+      t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE],
+      1024);
+  uint32_t threshold_to_send_transport_window_update =
+      t->outbuf.count > 0 ? 3 * target_incoming_window / 4
+                          : target_incoming_window / 2;
+  if (t->incoming_window <= threshold_to_send_transport_window_update) {
+    maybe_initiate_ping(exec_ctx, t,
+                        GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE);
+    uint32_t announced = (uint32_t)GPR_CLAMP(
+        target_incoming_window - t->incoming_window, 0, UINT32_MAX);
+    GRPC_CHTTP2_FLOW_CREDIT_TRANSPORT("write", t, incoming_window, announced);
     grpc_transport_one_way_stats throwaway_stats;
     grpc_slice_buffer_add(&t->outbuf, grpc_chttp2_window_update_create(
                                           0, announced, &throwaway_stats));
+    t->ping_state.pings_before_data_required =
+        t->ping_policy.max_pings_without_data;
+  }
+
+  for (size_t i = 0; i < t->ping_ack_count; i++) {
+    grpc_slice_buffer_add(&t->outbuf,
+                          grpc_chttp2_ping_create(1, t->ping_acks[i]));
   }
+  t->ping_ack_count = 0;
+
+  maybe_initiate_ping(exec_ctx, t, GRPC_CHTTP2_PING_ON_NEXT_WRITE);
 
   GPR_TIMER_END("grpc_chttp2_begin_write", 0);
 

src/core/lib/channel/connected_channel.c

@@ -140,7 +140,7 @@ static void con_get_channel_info(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem,
                                  const grpc_channel_info *channel_info) {}
 
-static const grpc_channel_filter connected_channel_filter = {
+const grpc_channel_filter grpc_connected_filter = {
     con_start_transport_stream_op,
     con_start_transport_op,
     sizeof(call_data),
@@ -158,7 +158,7 @@ static const grpc_channel_filter connected_channel_filter = {
 static void bind_transport(grpc_channel_stack *channel_stack,
                            grpc_channel_element *elem, void *t) {
   channel_data *cd = (channel_data *)elem->channel_data;
-  GPR_ASSERT(elem->filter == &connected_channel_filter);
+  GPR_ASSERT(elem->filter == &grpc_connected_filter);
   GPR_ASSERT(cd->transport == NULL);
   cd->transport = t;
 
@@ -178,7 +178,7 @@ bool grpc_add_connected_filter(grpc_exec_ctx *exec_ctx,
   grpc_transport *t = grpc_channel_stack_builder_get_transport(builder);
   GPR_ASSERT(t != NULL);
   return grpc_channel_stack_builder_append_filter(
-      builder, &connected_channel_filter, bind_transport, t);
+      builder, &grpc_connected_filter, bind_transport, t);
 }
 
 grpc_stream *grpc_connected_channel_get_stream(grpc_call_element *elem) {

src/core/lib/channel/connected_channel.h

@@ -36,8 +36,13 @@
 
 #include "src/core/lib/channel/channel_stack_builder.h"
 
+extern const grpc_channel_filter grpc_connected_filter;
+
 bool grpc_add_connected_filter(grpc_exec_ctx *exec_ctx,
                                grpc_channel_stack_builder *builder,
                                void *arg_must_be_null);
 
+/* Debug helper to dig the transport stream out of a call element */
+grpc_stream *grpc_connected_channel_get_stream(grpc_call_element *elem);
+
 #endif /* GRPC_CORE_LIB_CHANNEL_CONNECTED_CHANNEL_H */

src/core/lib/iomgr/closure.c

@@ -51,20 +51,22 @@ void grpc_closure_list_init(grpc_closure_list *closure_list) {
   closure_list->head = closure_list->tail = NULL;
 }
 
-void grpc_closure_list_append(grpc_closure_list *closure_list,
+bool grpc_closure_list_append(grpc_closure_list *closure_list,
                               grpc_closure *closure, grpc_error *error) {
   if (closure == NULL) {
     GRPC_ERROR_UNREF(error);
-    return;
+    return false;
   }
   closure->error_data.error = error;
   closure->next_data.next = NULL;
-  if (closure_list->head == NULL) {
+  bool was_empty = (closure_list->head == NULL);
+  if (was_empty) {
     closure_list->head = closure;
   } else {
     closure_list->tail->next_data.next = closure;
   }
   closure_list->tail = closure;
+  return was_empty;
 }
 
 void grpc_closure_list_fail_all(grpc_closure_list *list,

src/core/lib/iomgr/closure.h

@@ -116,8 +116,9 @@ grpc_closure *grpc_closure_create(grpc_iomgr_cb_func cb, void *cb_arg,
 void grpc_closure_list_init(grpc_closure_list *list);
 
 /** add \a closure to the end of \a list
-    and set \a closure's result to \a error */
-void grpc_closure_list_append(grpc_closure_list *list, grpc_closure *closure,
+    and set \a closure's result to \a error
+    Returns true if \a list becomes non-empty */
+bool grpc_closure_list_append(grpc_closure_list *list, grpc_closure *closure,
                               grpc_error *error);
 
 /** force all success bits in \a list to false */

src/core/lib/iomgr/combiner.c

@@ -72,6 +72,7 @@ struct grpc_combiner {
   bool final_list_covered_by_poller;
   grpc_closure_list final_list;
   grpc_closure offload;
+  gpr_refcount refs;
 };
 
 static void combiner_exec_uncovered(grpc_exec_ctx *exec_ctx,
@@ -126,6 +127,7 @@ static bool is_covered_by_poller(grpc_combiner *lock) {
 
 grpc_combiner *grpc_combiner_create(grpc_workqueue *optional_workqueue) {
   grpc_combiner *lock = gpr_malloc(sizeof(*lock));
+  gpr_ref_init(&lock->refs, 1);
   lock->next_combiner_on_this_exec_ctx = NULL;
   lock->time_to_execute_final_list = false;
   lock->optional_workqueue = optional_workqueue;
@@ -152,7 +154,7 @@ static void really_destroy(grpc_exec_ctx *exec_ctx, grpc_combiner *lock) {
   gpr_free(lock);
 }
 
-void grpc_combiner_destroy(grpc_exec_ctx *exec_ctx, grpc_combiner *lock) {
+static void start_destroy(grpc_exec_ctx *exec_ctx, grpc_combiner *lock) {
   gpr_atm old_state = gpr_atm_full_fetch_add(&lock->state, -STATE_UNORPHANED);
   GRPC_COMBINER_TRACE(gpr_log(
       GPR_DEBUG, "C:%p really_destroy old_state=%" PRIdPTR, lock, old_state));
@@ -161,6 +163,30 @@ void grpc_combiner_destroy(grpc_exec_ctx *exec_ctx, grpc_combiner *lock) {
   }
 }
 
+#ifdef GRPC_COMBINER_REFCOUNT_DEBUG
+#define GRPC_COMBINER_DEBUG_SPAM(op, delta)                               \
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,                             \
+          "combiner[%p] %s %" PRIdPTR " --> %" PRIdPTR " %s", lock, (op), \
+          gpr_atm_no_barrier_load(&lock->refs.count),                     \
+          gpr_atm_no_barrier_load(&lock->refs.count) + (delta), reason);
+#else
+#define GRPC_COMBINER_DEBUG_SPAM(op, delta)
+#endif
+
+void grpc_combiner_unref(grpc_exec_ctx *exec_ctx,
+                         grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS) {
+  GRPC_COMBINER_DEBUG_SPAM("UNREF", -1);
+  if (gpr_unref(&lock->refs)) {
+    start_destroy(exec_ctx, lock);
+  }
+}
+
+grpc_combiner *grpc_combiner_ref(grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS) {
+  GRPC_COMBINER_DEBUG_SPAM("  REF", 1);
+  gpr_ref(&lock->refs);
+  return lock;
+}
+
 static void push_last_on_exec_ctx(grpc_exec_ctx *exec_ctx,
                                   grpc_combiner *lock) {
   lock->next_combiner_on_this_exec_ctx = NULL;

src/core/lib/iomgr/combiner.h

@@ -48,8 +48,27 @@
 // Initialize the lock, with an optional workqueue to shift load to when
 // necessary
 grpc_combiner *grpc_combiner_create(grpc_workqueue *optional_workqueue);
-// Destroy the lock
-void grpc_combiner_destroy(grpc_exec_ctx *exec_ctx, grpc_combiner *lock);
+
+//#define GRPC_COMBINER_REFCOUNT_DEBUG
+#ifdef GRPC_COMBINER_REFCOUNT_DEBUG
+#define GRPC_COMBINER_DEBUG_ARGS \
+  , const char *file, int line, const char *reason
+#define GRPC_COMBINER_REF(combiner, reason) \
+  grpc_combiner_ref((combiner), __FILE__, __LINE__, (reason))
+#define GRPC_COMBINER_UNREF(exec_ctx, combiner, reason) \
+  grpc_combiner_unref((exec_ctx), (combiner), __FILE__, __LINE__, (reason))
+#else
+#define GRPC_COMBINER_DEBUG_ARGS
+#define GRPC_COMBINER_REF(combiner, reason) grpc_combiner_ref((combiner))
+#define GRPC_COMBINER_UNREF(exec_ctx, combiner, reason) \
+  grpc_combiner_unref((exec_ctx), (combiner))
+#endif
+
+// Ref/unref the lock, for when we're sharing the lock ownership
+// Prefer to use the macros above
+grpc_combiner *grpc_combiner_ref(grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS);
+void grpc_combiner_unref(grpc_exec_ctx *exec_ctx,
+                         grpc_combiner *lock GRPC_COMBINER_DEBUG_ARGS);
 // Fetch a scheduler to schedule closures against
 grpc_closure_scheduler *grpc_combiner_scheduler(grpc_combiner *lock,
                                                 bool covered_by_poller);

src/core/lib/iomgr/resource_quota.c

@@ -33,6 +33,8 @@
 
 #include "src/core/lib/iomgr/resource_quota.h"
 
+#include <limits.h>
+#include <stdint.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
@@ -44,6 +46,8 @@
 
 int grpc_resource_quota_trace = 0;
 
+#define MEMORY_USAGE_ESTIMATION_MAX 65536
+
 /* Internal linked list pointers for a resource user */
 typedef struct {
   grpc_resource_user *next;
@@ -126,9 +130,12 @@ struct grpc_resource_quota {
   /* refcount */
   gpr_refcount refs;
 
+  /* estimate of current memory usage
+     scaled to the range [0..RESOURCE_USAGE_ESTIMATION_MAX] */
+  gpr_atm memory_usage_estimation;
+
   /* Master combiner lock: all activity on a quota executes under this combiner
-   * (so no mutex is needed for this data structure)
-   */
+   * (so no mutex is needed for this data structure) */
   grpc_combiner *combiner;
   /* Size of the resource quota */
   int64_t size;
@@ -269,6 +276,16 @@ static void rq_step_sched(grpc_exec_ctx *exec_ctx,
                      GRPC_ERROR_NONE);
 }
 
+/* update the atomically available resource estimate - use no barriers since
+   timeliness of delivery really doesn't matter much */
+static void rq_update_estimate(grpc_resource_quota *resource_quota) {
+  gpr_atm_no_barrier_store(&resource_quota->memory_usage_estimation,
+                           (gpr_atm)((1.0 -
+                                      ((double)resource_quota->free_pool) /
+                                          ((double)resource_quota->size)) *
+                                     MEMORY_USAGE_ESTIMATION_MAX));
+}
+
 /* returns true if all allocations are completed */
 static bool rq_alloc(grpc_exec_ctx *exec_ctx,
                      grpc_resource_quota *resource_quota) {
@@ -281,6 +298,7 @@ static bool rq_alloc(grpc_exec_ctx *exec_ctx,
       int64_t amt = -resource_user->free_pool;
       resource_user->free_pool = 0;
       resource_quota->free_pool -= amt;
+      rq_update_estimate(resource_quota);
       if (grpc_resource_quota_trace) {
         gpr_log(GPR_DEBUG, "RQ %s %s: grant alloc %" PRId64
                            " bytes; rq_free_pool -> %" PRId64,
@@ -315,6 +333,7 @@ static bool rq_reclaim_from_per_user_free_pool(
       int64_t amt = resource_user->free_pool;
       resource_user->free_pool = 0;
       resource_quota->free_pool += amt;
+      rq_update_estimate(resource_quota);
       if (grpc_resource_quota_trace) {
         gpr_log(GPR_DEBUG, "RQ %s %s: reclaim_from_per_user_free_pool %" PRId64
                            " bytes; rq_free_pool -> %" PRId64,
@@ -531,6 +550,7 @@ static void rq_resize(grpc_exec_ctx *exec_ctx, void *args, grpc_error *error) {
   int64_t delta = a->size - a->resource_quota->size;
   a->resource_quota->size += delta;
   a->resource_quota->free_pool += delta;
+  rq_update_estimate(a->resource_quota);
   rq_step_sched(exec_ctx, a->resource_quota);
   grpc_resource_quota_unref_internal(exec_ctx, a->resource_quota);
   gpr_free(a);
@@ -557,6 +577,7 @@ grpc_resource_quota *grpc_resource_quota_create(const char *name) {
   resource_quota->size = INT64_MAX;
   resource_quota->step_scheduled = false;
   resource_quota->reclaiming = false;
+  gpr_atm_no_barrier_store(&resource_quota->memory_usage_estimation, 0);
   if (name != NULL) {
     resource_quota->name = gpr_strdup(name);
   } else {
@@ -578,7 +599,7 @@ grpc_resource_quota *grpc_resource_quota_create(const char *name) {
 void grpc_resource_quota_unref_internal(grpc_exec_ctx *exec_ctx,
                                         grpc_resource_quota *resource_quota) {
   if (gpr_unref(&resource_quota->refs)) {
-    grpc_combiner_destroy(exec_ctx, resource_quota->combiner);
+    GRPC_COMBINER_UNREF(exec_ctx, resource_quota->combiner, "resource_quota");
     gpr_free(resource_quota->name);
     gpr_free(resource_quota);
   }
@@ -602,6 +623,13 @@ void grpc_resource_quota_ref(grpc_resource_quota *resource_quota) {
   grpc_resource_quota_ref_internal(resource_quota);
 }
 
+double grpc_resource_quota_get_memory_pressure(
+    grpc_resource_quota *resource_quota) {
+  return ((double)(gpr_atm_no_barrier_load(
+             &resource_quota->memory_usage_estimation))) /
+         ((double)MEMORY_USAGE_ESTIMATION_MAX);
+}
+
 /* Public API */
 void grpc_resource_quota_resize(grpc_resource_quota *resource_quota,
                                 size_t size) {

src/core/lib/iomgr/resource_quota.h

@@ -84,6 +84,12 @@ void grpc_resource_quota_unref_internal(grpc_exec_ctx *exec_ctx,
 grpc_resource_quota *grpc_resource_quota_from_channel_args(
     const grpc_channel_args *channel_args);
 
+/* Return a number indicating current memory pressure:
+   0.0 ==> no memory usage
+   1.0 ==> maximum memory usage */
+double grpc_resource_quota_get_memory_pressure(
+    grpc_resource_quota *resource_quota);
+
 typedef struct grpc_resource_user grpc_resource_user;
 
 grpc_resource_user *grpc_resource_user_create(

src/core/lib/iomgr/sockaddr_utils.c

@@ -190,31 +190,37 @@ int grpc_sockaddr_to_string(char **out,
 }
 
 char *grpc_sockaddr_to_uri(const grpc_resolved_address *resolved_addr) {
-  char *temp;
-  char *result;
   grpc_resolved_address addr_normalized;
-  const struct sockaddr *addr;
-
   if (grpc_sockaddr_is_v4mapped(resolved_addr, &addr_normalized)) {
     resolved_addr = &addr_normalized;
   }
+  const char *scheme = grpc_sockaddr_get_uri_scheme(resolved_addr);
+  if (scheme == NULL || strcmp("unix", scheme) == 0) {
+    return grpc_sockaddr_to_uri_unix_if_possible(resolved_addr);
+  }
+  char *path = NULL;
+  char *uri_str = NULL;
+  if (grpc_sockaddr_to_string(&path, resolved_addr,
+                              false /* suppress errors */) &&
+      scheme != NULL) {
+    gpr_asprintf(&uri_str, "%s:%s", scheme, path);
+  }
+  gpr_free(path);
+  return uri_str != NULL ? uri_str : NULL;
+}
 
-  addr = (const struct sockaddr *)resolved_addr->addr;
-
+const char *grpc_sockaddr_get_uri_scheme(
+    const grpc_resolved_address *resolved_addr) {
+  const struct sockaddr *addr = (const struct sockaddr *)resolved_addr->addr;
   switch (addr->sa_family) {
     case AF_INET:
-      grpc_sockaddr_to_string(&temp, resolved_addr, 0);
-      gpr_asprintf(&result, "ipv4:%s", temp);
-      gpr_free(temp);
-      return result;
+      return "ipv4";
     case AF_INET6:
-      grpc_sockaddr_to_string(&temp, resolved_addr, 0);
-      gpr_asprintf(&result, "ipv6:%s", temp);
-      gpr_free(temp);
-      return result;
-    default:
-      return grpc_sockaddr_to_uri_unix_if_possible(resolved_addr);
+      return "ipv6";
+    case AF_UNIX:
+      return "unix";
   }
+  return NULL;
 }
 
 int grpc_sockaddr_get_port(const grpc_resolved_address *resolved_addr) {

src/core/lib/iomgr/sockaddr_utils.h

@@ -84,6 +84,10 @@ int grpc_sockaddr_set_port(const grpc_resolved_address *addr, int port);
 int grpc_sockaddr_to_string(char **out, const grpc_resolved_address *addr,
                             int normalize);
 
+/* Returns the URI string corresponding to \a addr */
 char *grpc_sockaddr_to_uri(const grpc_resolved_address *addr);
 
+/* Returns the URI scheme corresponding to \a addr */
+const char *grpc_sockaddr_get_uri_scheme(const grpc_resolved_address *addr);
+
 #endif /* GRPC_CORE_LIB_IOMGR_SOCKADDR_UTILS_H */

src/core/lib/iomgr/tcp_client_windows.c

@@ -135,12 +135,10 @@ static void on_connect(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
 
 /* Tries to issue one async connection, then schedules both an IOCP
    notification request for the connection, and one timeout alert. */
-void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *on_done,
-                             grpc_endpoint **endpoint,
-                             grpc_pollset_set *interested_parties,
-                             const grpc_channel_args *channel_args,
-                             const grpc_resolved_address *addr,
-                             gpr_timespec deadline) {
+static void tcp_client_connect_impl(
+    grpc_exec_ctx *exec_ctx, grpc_closure *on_done, grpc_endpoint **endpoint,
+    grpc_pollset_set *interested_parties, const grpc_channel_args *channel_args,
+    const grpc_resolved_address *addr, gpr_timespec deadline) {
   SOCKET sock = INVALID_SOCKET;
   BOOL success;
   int status;
@@ -252,4 +250,21 @@ failure:
   grpc_closure_sched(exec_ctx, on_done, final_error);
 }
 
+// overridden by api_fuzzer.c
+void (*grpc_tcp_client_connect_impl)(
+    grpc_exec_ctx *exec_ctx, grpc_closure *closure, grpc_endpoint **ep,
+    grpc_pollset_set *interested_parties, const grpc_channel_args *channel_args,
+    const grpc_resolved_address *addr,
+    gpr_timespec deadline) = tcp_client_connect_impl;
+
+void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                             grpc_endpoint **ep,
+                             grpc_pollset_set *interested_parties,
+                             const grpc_channel_args *channel_args,
+                             const grpc_resolved_address *addr,
+                             gpr_timespec deadline) {
+  grpc_tcp_client_connect_impl(exec_ctx, closure, ep, interested_parties,
+                               channel_args, addr, deadline);
+}
+
 #endif /* GRPC_WINSOCK_SOCKET */

src/core/lib/iomgr/tcp_server_posix.c

@@ -44,6 +44,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <ifaddrs.h>
 #include <limits.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
@@ -115,6 +116,8 @@ struct grpc_tcp_server {
   bool shutdown;
   /* use SO_REUSEPORT */
   bool so_reuseport;
+  /* expand wildcard addresses to a list of all local addresses */
+  bool expand_wildcard_addrs;
 
   /* linked list of server ports */
   grpc_tcp_listener *head;
@@ -161,6 +164,7 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
   grpc_tcp_server *s = gpr_malloc(sizeof(grpc_tcp_server));
   s->so_reuseport = has_so_reuseport;
   s->resource_quota = grpc_resource_quota_create(NULL);
+  s->expand_wildcard_addrs = false;
   for (size_t i = 0; i < (args == NULL ? 0 : args->num_args); i++) {
     if (0 == strcmp(GRPC_ARG_ALLOW_REUSEPORT, args->args[i].key)) {
       if (args->args[i].type == GRPC_ARG_INTEGER) {
@@ -183,6 +187,15 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
         return GRPC_ERROR_CREATE(GRPC_ARG_RESOURCE_QUOTA
                                  " must be a pointer to a buffer pool");
       }
+    } else if (0 == strcmp(GRPC_ARG_EXPAND_WILDCARD_ADDRS, args->args[i].key)) {
+      if (args->args[i].type == GRPC_ARG_INTEGER) {
+        s->expand_wildcard_addrs = (args->args[i].value.integer != 0);
+      } else {
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
+        gpr_free(s);
+        return GRPC_ERROR_CREATE(GRPC_ARG_EXPAND_WILDCARD_ADDRS
+                                 " must be an integer");
+      }
     }
   }
   gpr_ref_init(&s->refs, 1);
@@ -504,9 +517,224 @@ static grpc_error *add_socket_to_server(grpc_tcp_server *s, int fd,
   return err;
 }
 
-/* Insert count new listeners after listener. Every new listener will have the
-   same listen address as listener (SO_REUSEPORT must be enabled). Every new
-   listener is a sibling of listener. */
+/* If successful, add a listener to s for addr, set *dsmode for the socket, and
+   return the *listener. */
+static grpc_error *add_addr_to_server(grpc_tcp_server *s,
+                                      const grpc_resolved_address *addr,
+                                      unsigned port_index, unsigned fd_index,
+                                      grpc_dualstack_mode *dsmode,
+                                      grpc_tcp_listener **listener) {
+  grpc_resolved_address addr4_copy;
+  int fd;
+  grpc_error *err =
+      grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, dsmode, &fd);
+  if (err != GRPC_ERROR_NONE) {
+    return err;
+  }
+  if (*dsmode == GRPC_DSMODE_IPV4 &&
+      grpc_sockaddr_is_v4mapped(addr, &addr4_copy)) {
+    addr = &addr4_copy;
+  }
+  return add_socket_to_server(s, fd, addr, port_index, fd_index, listener);
+}
+
+/* Bind to "::" to get a port number not used by any address. */
+static grpc_error *get_unused_port(int *port) {
+  grpc_resolved_address wild;
+  grpc_sockaddr_make_wildcard6(0, &wild);
+  grpc_dualstack_mode dsmode;
+  int fd;
+  grpc_error *err =
+      grpc_create_dualstack_socket(&wild, SOCK_STREAM, 0, &dsmode, &fd);
+  if (err != GRPC_ERROR_NONE) {
+    return err;
+  }
+  if (dsmode == GRPC_DSMODE_IPV4) {
+    grpc_sockaddr_make_wildcard4(0, &wild);
+  }
+  if (bind(fd, (const struct sockaddr *)wild.addr, (socklen_t)wild.len) != 0) {
+    err = GRPC_OS_ERROR(errno, "bind");
+    close(fd);
+    return err;
+  }
+  if (getsockname(fd, (struct sockaddr *)wild.addr, (socklen_t *)&wild.len) !=
+      0) {
+    err = GRPC_OS_ERROR(errno, "getsockname");
+    close(fd);
+    return err;
+  }
+  close(fd);
+  *port = grpc_sockaddr_get_port(&wild);
+  return *port <= 0 ? GRPC_ERROR_CREATE("Bad port") : GRPC_ERROR_NONE;
+}
+
+/* Return the listener in s with address addr or NULL. */
+static grpc_tcp_listener *find_listener_with_addr(grpc_tcp_server *s,
+                                                  grpc_resolved_address *addr) {
+  grpc_tcp_listener *l;
+  gpr_mu_lock(&s->mu);
+  for (l = s->head; l != NULL; l = l->next) {
+    if (l->addr.len != addr->len) {
+      continue;
+    }
+    if (memcmp(l->addr.addr, addr->addr, addr->len) == 0) {
+      break;
+    }
+  }
+  gpr_mu_unlock(&s->mu);
+  return l;
+}
+
+/* Get all addresses assigned to network interfaces on the machine and create a
+   listener for each. requested_port is the port to use for every listener, or 0
+   to select one random port that will be used for every listener. Set *out_port
+   to the port selected. Return GRPC_ERROR_NONE only if all listeners were
+   added. */
+static grpc_error *add_all_local_addrs_to_server(grpc_tcp_server *s,
+                                                 unsigned port_index,
+                                                 int requested_port,
+                                                 int *out_port) {
+  struct ifaddrs *ifa = NULL;
+  struct ifaddrs *ifa_it;
+  unsigned fd_index = 0;
+  grpc_tcp_listener *sp = NULL;
+  grpc_error *err = GRPC_ERROR_NONE;
+  if (requested_port == 0) {
+    /* Note: There could be a race where some local addrs can listen on the
+       selected port and some can't. The sane way to handle this would be to
+       retry by recreating the whole grpc_tcp_server. Backing out individual
+       listeners and orphaning the FDs looks like too much trouble. */
+    if ((err = get_unused_port(&requested_port)) != GRPC_ERROR_NONE) {
+      return err;
+    } else if (requested_port <= 0) {
+      return GRPC_ERROR_CREATE("Bad get_unused_port()");
+    }
+    gpr_log(GPR_DEBUG, "Picked unused port %d", requested_port);
+  }
+  if (getifaddrs(&ifa) != 0 || ifa == NULL) {
+    return GRPC_OS_ERROR(errno, "getifaddrs");
+  }
+  for (ifa_it = ifa; ifa_it != NULL; ifa_it = ifa_it->ifa_next) {
+    grpc_resolved_address addr;
+    char *addr_str = NULL;
+    grpc_dualstack_mode dsmode;
+    grpc_tcp_listener *new_sp = NULL;
+    const char *ifa_name = (ifa_it->ifa_name ? ifa_it->ifa_name : "<unknown>");
+    if (ifa_it->ifa_addr == NULL) {
+      continue;
+    } else if (ifa_it->ifa_addr->sa_family == AF_INET) {
+      addr.len = sizeof(struct sockaddr_in);
+    } else if (ifa_it->ifa_addr->sa_family == AF_INET6) {
+      addr.len = sizeof(struct sockaddr_in6);
+    } else {
+      continue;
+    }
+    memcpy(addr.addr, ifa_it->ifa_addr, addr.len);
+    if (!grpc_sockaddr_set_port(&addr, requested_port)) {
+      /* Should never happen, because we check sa_family above. */
+      err = GRPC_ERROR_CREATE("Failed to set port");
+      break;
+    }
+    if (grpc_sockaddr_to_string(&addr_str, &addr, 0) < 0) {
+      addr_str = gpr_strdup("<error>");
+    }
+    gpr_log(GPR_DEBUG,
+            "Adding local addr from interface %s flags 0x%x to server: %s",
+            ifa_name, ifa_it->ifa_flags, addr_str);
+    /* We could have multiple interfaces with the same address (e.g., bonding),
+       so look for duplicates. */
+    if (find_listener_with_addr(s, &addr) != NULL) {
+      gpr_log(GPR_DEBUG, "Skipping duplicate addr %s on interface %s", addr_str,
+              ifa_name);
+      gpr_free(addr_str);
+      continue;
+    }
+    if ((err = add_addr_to_server(s, &addr, port_index, fd_index, &dsmode,
+                                  &new_sp)) != GRPC_ERROR_NONE) {
+      char *err_str = NULL;
+      grpc_error *root_err;
+      if (gpr_asprintf(&err_str, "Failed to add listener: %s", addr_str) < 0) {
+        err_str = gpr_strdup("Failed to add listener");
+      }
+      root_err = GRPC_ERROR_CREATE(err_str);
+      gpr_free(err_str);
+      gpr_free(addr_str);
+      err = grpc_error_add_child(root_err, err);
+      break;
+    } else {
+      GPR_ASSERT(requested_port == new_sp->port);
+      ++fd_index;
+      if (sp != NULL) {
+        new_sp->is_sibling = 1;
+        sp->sibling = new_sp;
+      }
+      sp = new_sp;
+    }
+    gpr_free(addr_str);
+  }
+  freeifaddrs(ifa);
+  if (err != GRPC_ERROR_NONE) {
+    return err;
+  } else if (sp == NULL) {
+    return GRPC_ERROR_CREATE("No local addresses");
+  } else {
+    *out_port = sp->port;
+    return GRPC_ERROR_NONE;
+  }
+}
+
+/* Treat :: or 0.0.0.0 as a family-agnostic wildcard. */
+static grpc_error *add_wildcard_addrs_to_server(grpc_tcp_server *s,
+                                                unsigned port_index,
+                                                int requested_port,
+                                                int *out_port) {
+  grpc_resolved_address wild4;
+  grpc_resolved_address wild6;
+  unsigned fd_index = 0;
+  grpc_dualstack_mode dsmode;
+  grpc_tcp_listener *sp = NULL;
+  grpc_tcp_listener *sp2 = NULL;
+  grpc_error *v6_err = GRPC_ERROR_NONE;
+  grpc_error *v4_err = GRPC_ERROR_NONE;
+  *out_port = -1;
+  if (s->expand_wildcard_addrs) {
+    return add_all_local_addrs_to_server(s, port_index, requested_port,
+                                         out_port);
+  }
+  grpc_sockaddr_make_wildcards(requested_port, &wild4, &wild6);
+  /* Try listening on IPv6 first. */
+  if ((v6_err = add_addr_to_server(s, &wild6, port_index, fd_index, &dsmode,
+                                   &sp)) == GRPC_ERROR_NONE) {
+    ++fd_index;
+    requested_port = *out_port = sp->port;
+    if (dsmode == GRPC_DSMODE_DUALSTACK || dsmode == GRPC_DSMODE_IPV4) {
+      return GRPC_ERROR_NONE;
+    }
+  }
+  /* If we got a v6-only socket or nothing, try adding 0.0.0.0. */
+  grpc_sockaddr_set_port(&wild4, requested_port);
+  if ((v4_err = add_addr_to_server(s, &wild4, port_index, fd_index, &dsmode,
+                                   &sp2)) == GRPC_ERROR_NONE) {
+    *out_port = sp2->port;
+    if (sp != NULL) {
+      sp2->is_sibling = 1;
+      sp->sibling = sp2;
+    }
+  }
+  if (*out_port > 0) {
+    GRPC_LOG_IF_ERROR("Failed to add :: listener", v6_err);
+    GRPC_LOG_IF_ERROR("Failed to add 0.0.0.0 listener", v4_err);
+    return GRPC_ERROR_NONE;
+  } else {
+    grpc_error *root_err =
+        GRPC_ERROR_CREATE("Failed to add any wildcard listeners");
+    GPR_ASSERT(v6_err != GRPC_ERROR_NONE && v4_err != GRPC_ERROR_NONE);
+    root_err = grpc_error_add_child(root_err, v6_err);
+    root_err = grpc_error_add_child(root_err, v4_err);
+    return root_err;
+  }
+}
+
 static grpc_error *clone_port(grpc_tcp_listener *listener, unsigned count) {
   grpc_tcp_listener *sp = NULL;
   char *addr_str;
@@ -559,19 +787,13 @@ grpc_error *grpc_tcp_server_add_port(grpc_tcp_server *s,
                                      const grpc_resolved_address *addr,
                                      int *out_port) {
   grpc_tcp_listener *sp;
-  grpc_tcp_listener *sp2 = NULL;
-  int fd;
-  grpc_dualstack_mode dsmode;
-  grpc_resolved_address addr6_v4mapped;
-  grpc_resolved_address wild4;
-  grpc_resolved_address wild6;
-  grpc_resolved_address addr4_copy;
-  grpc_resolved_address *allocated_addr = NULL;
   grpc_resolved_address sockname_temp;
-  int port;
+  grpc_resolved_address addr6_v4mapped;
+  int requested_port = grpc_sockaddr_get_port(addr);
   unsigned port_index = 0;
-  unsigned fd_index = 0;
-  grpc_error *errs[2] = {GRPC_ERROR_NONE, GRPC_ERROR_NONE};
+  grpc_dualstack_mode dsmode;
+  grpc_error *err;
+  *out_port = -1;
   if (s->tail != NULL) {
     port_index = s->tail->port_index + 1;
   }
@@ -579,85 +801,34 @@ grpc_error *grpc_tcp_server_add_port(grpc_tcp_server *s,
 
   /* Check if this is a wildcard port, and if so, try to keep the port the same
      as some previously created listener. */
-  if (grpc_sockaddr_get_port(addr) == 0) {
+  if (requested_port == 0) {
     for (sp = s->head; sp; sp = sp->next) {
       sockname_temp.len = sizeof(struct sockaddr_storage);
-      if (0 == getsockname(sp->fd, (struct sockaddr *)sockname_temp.addr,
+      if (0 == getsockname(sp->fd, (struct sockaddr *)&sockname_temp.addr,
                            (socklen_t *)&sockname_temp.len)) {
-        port = grpc_sockaddr_get_port(&sockname_temp);
-        if (port > 0) {
-          allocated_addr = gpr_malloc(sizeof(grpc_resolved_address));
-          memcpy(allocated_addr, addr, addr->len);
-          grpc_sockaddr_set_port(allocated_addr, port);
-          addr = allocated_addr;
+        int used_port = grpc_sockaddr_get_port(&sockname_temp);
+        if (used_port > 0) {
+          memcpy(&sockname_temp, addr, sizeof(grpc_resolved_address));
+          grpc_sockaddr_set_port(&sockname_temp, used_port);
+          requested_port = used_port;
+          addr = &sockname_temp;
           break;
         }
       }
     }
   }
-
-  sp = NULL;
-
+  if (grpc_sockaddr_is_wildcard(addr, &requested_port)) {
+    return add_wildcard_addrs_to_server(s, port_index, requested_port,
+                                        out_port);
+  }
   if (grpc_sockaddr_to_v4mapped(addr, &addr6_v4mapped)) {
     addr = &addr6_v4mapped;
   }
-
-  /* Treat :: or 0.0.0.0 as a family-agnostic wildcard. */
-  if (grpc_sockaddr_is_wildcard(addr, &port)) {
-    grpc_sockaddr_make_wildcards(port, &wild4, &wild6);
-
-    /* Try listening on IPv6 first. */
-    addr = &wild6;
-    errs[0] = grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, &dsmode, &fd);
-    if (errs[0] == GRPC_ERROR_NONE) {
-      errs[0] = add_socket_to_server(s, fd, addr, port_index, fd_index, &sp);
-      if (fd >= 0 && dsmode == GRPC_DSMODE_DUALSTACK) {
-        goto done;
-      }
-      if (sp != NULL) {
-        ++fd_index;
-      }
-      /* If we didn't get a dualstack socket, also listen on 0.0.0.0. */
-      if (port == 0 && sp != NULL) {
-        grpc_sockaddr_set_port(&wild4, sp->port);
-      }
-    }
-    addr = &wild4;
-  }
-
-  errs[1] = grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, &dsmode, &fd);
-  if (errs[1] == GRPC_ERROR_NONE) {
-    if (dsmode == GRPC_DSMODE_IPV4 &&
-        grpc_sockaddr_is_v4mapped(addr, &addr4_copy)) {
-      addr = &addr4_copy;
-    }
-    sp2 = sp;
-    errs[1] = add_socket_to_server(s, fd, addr, port_index, fd_index, &sp);
-    if (sp2 != NULL && sp != NULL) {
-      sp2->sibling = sp;
-      sp->is_sibling = 1;
-    }
-  }
-
-done:
-  gpr_free(allocated_addr);
-  if (sp != NULL) {
+  if ((err = add_addr_to_server(s, addr, port_index, 0, &dsmode, &sp)) ==
+      GRPC_ERROR_NONE) {
     *out_port = sp->port;
-    GRPC_ERROR_UNREF(errs[0]);
-    GRPC_ERROR_UNREF(errs[1]);
-    return GRPC_ERROR_NONE;
-  } else {
-    *out_port = -1;
-    char *addr_str = grpc_sockaddr_to_uri(addr);
-    grpc_error *err = grpc_error_set_str(
-        GRPC_ERROR_CREATE_REFERENCING("Failed to add port to server", errs,
-                                      GPR_ARRAY_SIZE(errs)),
-        GRPC_ERROR_STR_TARGET_ADDRESS, addr_str);
-    GRPC_ERROR_UNREF(errs[0]);
-    GRPC_ERROR_UNREF(errs[1]);
-    gpr_free(addr_str);
-    return err;
   }
+  return err;
 }
 
 /* Return listener at port_index or NULL. Should only be called with s->mu

src/core/lib/iomgr/udp_server.c

@@ -76,8 +76,10 @@ struct grpc_udp_listener {
   grpc_udp_server *server;
   grpc_resolved_address addr;
   grpc_closure read_closure;
+  grpc_closure write_closure;
   grpc_closure destroyed_closure;
   grpc_udp_server_read_cb read_cb;
+  grpc_udp_server_write_cb write_cb;
   grpc_udp_server_orphan_cb orphan_cb;
 
   struct grpc_udp_listener *next;
@@ -176,7 +178,7 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
       /* Call the orphan_cb to signal that the FD is about to be closed and
        * should no longer be used. */
       GPR_ASSERT(sp->orphan_cb);
-      sp->orphan_cb(sp->emfd);
+      sp->orphan_cb(exec_ctx, sp->emfd);
 
       grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure, NULL,
                      "udp_listener_shutdown");
@@ -202,7 +204,7 @@ void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
   if (s->active_ports) {
     for (sp = s->head; sp; sp = sp->next) {
       GPR_ASSERT(sp->orphan_cb);
-      sp->orphan_cb(sp->emfd);
+      sp->orphan_cb(exec_ctx, sp->emfd);
       grpc_fd_shutdown(exec_ctx, sp->emfd,
                        GRPC_ERROR_CREATE("Server destroyed"));
     }
@@ -304,9 +306,33 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
   gpr_mu_unlock(&sp->server->mu);
 }
 
+static void on_write(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
+  grpc_udp_listener *sp = arg;
+
+  gpr_mu_lock(&(sp->server->mu));
+  if (error != GRPC_ERROR_NONE) {
+    if (0 == --sp->server->active_ports) {
+      gpr_mu_unlock(&sp->server->mu);
+      deactivated_all_ports(exec_ctx, sp->server);
+    } else {
+      gpr_mu_unlock(&sp->server->mu);
+    }
+    return;
+  }
+
+  /* Tell the registered callback that the socket is writeable. */
+  GPR_ASSERT(sp->write_cb);
+  sp->write_cb(exec_ctx, sp->emfd);
+
+  /* Re-arm the notification event so we get another chance to write. */
+  grpc_fd_notify_on_write(exec_ctx, sp->emfd, &sp->write_closure);
+  gpr_mu_unlock(&sp->server->mu);
+}
+
 static int add_socket_to_server(grpc_udp_server *s, int fd,
                                 const grpc_resolved_address *addr,
                                 grpc_udp_server_read_cb read_cb,
+                                grpc_udp_server_write_cb write_cb,
                                 grpc_udp_server_orphan_cb orphan_cb) {
   grpc_udp_listener *sp;
   int port;
@@ -333,6 +359,7 @@ static int add_socket_to_server(grpc_udp_server *s, int fd,
     sp->emfd = grpc_fd_create(fd, name);
     memcpy(&sp->addr, addr, sizeof(grpc_resolved_address));
     sp->read_cb = read_cb;
+    sp->write_cb = write_cb;
     sp->orphan_cb = orphan_cb;
     GPR_ASSERT(sp->emfd);
     gpr_mu_unlock(&s->mu);
@@ -345,6 +372,7 @@ static int add_socket_to_server(grpc_udp_server *s, int fd,
 int grpc_udp_server_add_port(grpc_udp_server *s,
                              const grpc_resolved_address *addr,
                              grpc_udp_server_read_cb read_cb,
+                             grpc_udp_server_write_cb write_cb,
                              grpc_udp_server_orphan_cb orphan_cb) {
   grpc_udp_listener *sp;
   int allocated_port1 = -1;
@@ -391,7 +419,8 @@ int grpc_udp_server_add_port(grpc_udp_server *s,
     // TODO(rjshade): Test and propagate the returned grpc_error*:
     GRPC_ERROR_UNREF(grpc_create_dualstack_socket(addr, SOCK_DGRAM, IPPROTO_UDP,
                                                   &dsmode, &fd));
-    allocated_port1 = add_socket_to_server(s, fd, addr, read_cb, orphan_cb);
+    allocated_port1 =
+        add_socket_to_server(s, fd, addr, read_cb, write_cb, orphan_cb);
     if (fd >= 0 && dsmode == GRPC_DSMODE_DUALSTACK) {
       goto done;
     }
@@ -413,7 +442,8 @@ int grpc_udp_server_add_port(grpc_udp_server *s,
       grpc_sockaddr_is_v4mapped(addr, &addr4_copy)) {
     addr = &addr4_copy;
   }
-  allocated_port2 = add_socket_to_server(s, fd, addr, read_cb, orphan_cb);
+  allocated_port2 =
+      add_socket_to_server(s, fd, addr, read_cb, write_cb, orphan_cb);
 
 done:
   gpr_free(allocated_addr);
@@ -451,6 +481,10 @@ void grpc_udp_server_start(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
                       grpc_schedule_on_exec_ctx);
     grpc_fd_notify_on_read(exec_ctx, sp->emfd, &sp->read_closure);
 
+    grpc_closure_init(&sp->write_closure, on_write, sp,
+                      grpc_schedule_on_exec_ctx);
+    grpc_fd_notify_on_write(exec_ctx, sp->emfd, &sp->write_closure);
+
     s->active_ports++;
     sp = sp->next;
   }

src/core/lib/iomgr/udp_server.h

@@ -49,8 +49,13 @@ typedef struct grpc_udp_server grpc_udp_server;
 typedef void (*grpc_udp_server_read_cb)(grpc_exec_ctx *exec_ctx, grpc_fd *emfd,
                                         struct grpc_server *server);
 
+/* Called when the socket is writeable. */
+typedef void (*grpc_udp_server_write_cb)(grpc_exec_ctx *exec_ctx,
+                                         grpc_fd *emfd);
+
 /* Called when the grpc_fd is about to be orphaned (and the FD closed). */
-typedef void (*grpc_udp_server_orphan_cb)(grpc_fd *emfd);
+typedef void (*grpc_udp_server_orphan_cb)(grpc_exec_ctx *exec_ctx,
+                                          grpc_fd *emfd);
 
 /* Create a server, initially not bound to any ports */
 grpc_udp_server *grpc_udp_server_create(void);
@@ -75,6 +80,7 @@ int grpc_udp_server_get_fd(grpc_udp_server *s, unsigned port_index);
 int grpc_udp_server_add_port(grpc_udp_server *s,
                              const grpc_resolved_address *addr,
                              grpc_udp_server_read_cb read_cb,
+                             grpc_udp_server_write_cb write_cb,
                              grpc_udp_server_orphan_cb orphan_cb);
 
 void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *server,

src/core/lib/profiling/basic_timers.c

@@ -43,6 +43,9 @@
 #include <grpc/support/thd.h>
 #include <grpc/support/time.h>
 #include <stdio.h>
+#include <string.h>
+
+#include "src/core/lib/support/env.h"
 
 typedef enum { BEGIN = '{', END = '}', MARK = '.' } marker_type;
 
@@ -74,7 +77,7 @@ typedef struct gpr_timer_log_list {
 static __thread gpr_timer_log *g_thread_log;
 static gpr_once g_once_init = GPR_ONCE_INIT;
 static FILE *output_file;
-static const char *output_filename = "latency_trace.txt";
+static const char *output_filename_or_null = NULL;
 static pthread_mutex_t g_mu;
 static pthread_cond_t g_cv;
 static gpr_timer_log_list g_in_progress_logs;
@@ -85,6 +88,17 @@ static __thread int g_thread_id;
 static int g_next_thread_id;
 static int g_writing_enabled = 1;
 
+static const char *output_filename() {
+  if (output_filename_or_null == NULL) {
+    output_filename_or_null = gpr_getenv("LATENCY_TRACE");
+    if (output_filename_or_null == NULL ||
+        strlen(output_filename_or_null) == 0) {
+      output_filename_or_null = "latency_trace.txt";
+    }
+  }
+  return output_filename_or_null;
+}
+
 static int timer_log_push_back(gpr_timer_log_list *list, gpr_timer_log *log) {
   if (list->head == NULL) {
     list->head = list->tail = log;
@@ -134,7 +148,7 @@ static void timer_log_remove(gpr_timer_log_list *list, gpr_timer_log *log) {
 static void write_log(gpr_timer_log *log) {
   size_t i;
   if (output_file == NULL) {
-    output_file = fopen(output_filename, "w");
+    output_file = fopen(output_filename(), "w");
   }
   for (i = 0; i < log->num_entries; i++) {
     gpr_timer_entry *entry = &(log->log[i]);
@@ -198,7 +212,7 @@ static void finish_writing(void) {
 }
 
 void gpr_timers_set_log_filename(const char *filename) {
-  output_filename = filename;
+  output_filename_or_null = filename;
 }
 
 static void init_output() {

src/core/lib/security/credentials/credentials.c

@@ -160,6 +160,53 @@ grpc_channel_credentials_duplicate_without_call_credentials(
   }
 }
 
+static void credentials_pointer_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
+  grpc_channel_credentials_unref(exec_ctx, p);
+}
+
+static void *credentials_pointer_arg_copy(void *p) {
+  return grpc_channel_credentials_ref(p);
+}
+
+static int credentials_pointer_cmp(void *a, void *b) { return GPR_ICMP(a, b); }
+
+static const grpc_arg_pointer_vtable credentials_pointer_vtable = {
+    credentials_pointer_arg_copy, credentials_pointer_arg_destroy,
+    credentials_pointer_cmp};
+
+grpc_arg grpc_channel_credentials_to_arg(
+    grpc_channel_credentials *credentials) {
+  grpc_arg result;
+  result.type = GRPC_ARG_POINTER;
+  result.key = GRPC_ARG_CHANNEL_CREDENTIALS;
+  result.value.pointer.vtable = &credentials_pointer_vtable;
+  result.value.pointer.p = credentials;
+  return result;
+}
+
+grpc_channel_credentials *grpc_channel_credentials_from_arg(
+    const grpc_arg *arg) {
+  if (strcmp(arg->key, GRPC_ARG_CHANNEL_CREDENTIALS)) return NULL;
+  if (arg->type != GRPC_ARG_POINTER) {
+    gpr_log(GPR_ERROR, "Invalid type %d for arg %s", arg->type,
+            GRPC_ARG_CHANNEL_CREDENTIALS);
+    return NULL;
+  }
+  return arg->value.pointer.p;
+}
+
+grpc_channel_credentials *grpc_channel_credentials_find_in_args(
+    const grpc_channel_args *args) {
+  size_t i;
+  if (args == NULL) return NULL;
+  for (i = 0; i < args->num_args; i++) {
+    grpc_channel_credentials *credentials =
+        grpc_channel_credentials_from_arg(&args->args[i]);
+    if (credentials != NULL) return credentials;
+  }
+  return NULL;
+}
+
 grpc_server_credentials *grpc_server_credentials_ref(
     grpc_server_credentials *creds) {
   if (creds == NULL) return NULL;

src/core/lib/security/credentials/credentials.h

@@ -100,6 +100,8 @@ void grpc_override_well_known_credentials_path_getter(
 
 /* --- grpc_channel_credentials. --- */
 
+#define GRPC_ARG_CHANNEL_CREDENTIALS "grpc.channel_credentials"
+
 typedef struct {
   void (*destruct)(grpc_exec_ctx *exec_ctx, grpc_channel_credentials *c);
 
@@ -140,6 +142,17 @@ grpc_channel_credentials *
 grpc_channel_credentials_duplicate_without_call_credentials(
     grpc_channel_credentials *creds);
 
+/* Util to encapsulate the channel credentials in a channel arg. */
+grpc_arg grpc_channel_credentials_to_arg(grpc_channel_credentials *credentials);
+
+/* Util to get the channel credentials from a channel arg. */
+grpc_channel_credentials *grpc_channel_credentials_from_arg(
+    const grpc_arg *arg);
+
+/* Util to find the channel credentials from channel args. */
+grpc_channel_credentials *grpc_channel_credentials_find_in_args(
+    const grpc_channel_args *args);
+
 /* --- grpc_credentials_md. --- */
 
 typedef struct {

src/core/lib/security/credentials/fake/fake_credentials.c

@@ -35,13 +35,13 @@
 
 #include <string.h>
 
-#include "src/core/lib/channel/channel_args.h"
-#include "src/core/lib/iomgr/executor.h"
-
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/lib/iomgr/executor.h"
+#include "src/core/lib/support/string.h"
+
 /* -- Fake transport security credentials. -- */
 
 static grpc_security_status fake_transport_security_create_security_connector(
@@ -49,7 +49,7 @@ static grpc_security_status fake_transport_security_create_security_connector(
     grpc_call_credentials *call_creds, const char *target,
     const grpc_channel_args *args, grpc_channel_security_connector **sc,
     grpc_channel_args **new_args) {
-  *sc = grpc_fake_channel_security_connector_create(call_creds);
+  *sc = grpc_fake_channel_security_connector_create(call_creds, target, args);
   return GRPC_SECURITY_OK;
 }
 

src/core/lib/security/credentials/fake/fake_credentials.h

@@ -38,6 +38,21 @@
 
 /* -- Fake transport security credentials. -- */
 
+/* Used to verify the target names given to the fake transport security
+ * connector.
+ *
+ * Its syntax by example:
+ * For LB channels:
+ *     "backend_target_1,backend_target_2,...;lb_target_1,lb_target_2,..."
+ * For regular channels:
+ *     "backend_taget_1,backend_target_2,..."
+ *
+ * That is to say, LB channels have a heading list of LB targets separated from
+ * the list of backend targets by a semicolon. For non-LB channels, only the
+ * latter is present. */
+#define GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS \
+  "grpc.test_only.fake_security.expected_target"
+
 /* Creates a fake transport security credentials object for testing. */
 grpc_channel_credentials *grpc_fake_transport_security_credentials_create(void);
 

src/core/lib/security/transport/client_auth_filter.c

@@ -335,7 +335,7 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
                                      grpc_channel_element *elem,
                                      grpc_channel_element_args *args) {
   grpc_security_connector *sc =
-      grpc_find_security_connector_in_args(args->channel_args);
+      grpc_security_connector_find_in_args(args->channel_args);
   grpc_auth_context *auth_context =
       grpc_find_auth_context_in_args(args->channel_args);
 

src/core/lib/security/transport/lb_targets_info.c

@@ -0,0 +1,70 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/log.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/security/transport/lb_targets_info.h"
+
+/* Channel arg key for the mapping of LB server addresses to their names for
+ * secure naming purposes. */
+#define GRPC_ARG_LB_SECURE_NAMING_MAP "grpc.lb_secure_naming_map"
+
+static void *targets_info_copy(void *p) { return grpc_slice_hash_table_ref(p); }
+static void targets_info_destroy(grpc_exec_ctx *exec_ctx, void *p) {
+  grpc_slice_hash_table_unref(exec_ctx, p);
+}
+static int targets_info_cmp(void *a, void *b) { return GPR_ICMP(a, b); }
+static const grpc_arg_pointer_vtable server_to_balancer_names_vtable = {
+    targets_info_copy, targets_info_destroy, targets_info_cmp};
+
+grpc_arg grpc_lb_targets_info_create_channel_arg(
+    grpc_slice_hash_table *targets_info) {
+  grpc_arg arg;
+  arg.type = GRPC_ARG_POINTER;
+  arg.key = GRPC_ARG_LB_SECURE_NAMING_MAP;
+  arg.value.pointer.p = targets_info;
+  arg.value.pointer.vtable = &server_to_balancer_names_vtable;
+  return arg;
+}
+
+grpc_slice_hash_table *grpc_lb_targets_info_find_in_args(
+    const grpc_channel_args *args) {
+  const grpc_arg *targets_info_arg =
+      grpc_channel_args_find(args, GRPC_ARG_LB_SECURE_NAMING_MAP);
+  if (targets_info_arg != NULL) {
+    GPR_ASSERT(targets_info_arg->type == GRPC_ARG_POINTER);
+    return targets_info_arg->value.pointer.p;
+  }
+  return NULL;
+}

src/core/lib/security/transport/lb_targets_info.h

@@ -0,0 +1,47 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SECURITY_TRANSPORT_LB_TARGETS_INFO_H
+#define GRPC_CORE_LIB_SECURITY_TRANSPORT_LB_TARGETS_INFO_H
+
+#include "src/core/lib/slice/slice_hash_table.h"
+
+/** Return a channel argument containing \a targets_info. */
+grpc_arg grpc_lb_targets_info_create_channel_arg(
+    grpc_slice_hash_table *targets_info);
+
+/** Return the instance of targets info in \a args or NULL */
+grpc_slice_hash_table *grpc_lb_targets_info_find_in_args(
+    const grpc_channel_args *args);
+
+#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_LB_TARGETS_INFO_H */

src/core/lib/security/transport/security_connector.c

@@ -43,10 +43,13 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/transport/chttp2/alpn/alpn.h"
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/handshaker.h"
 #include "src/core/lib/iomgr/load_file.h"
 #include "src/core/lib/security/context/security_context.h"
 #include "src/core/lib/security/credentials/credentials.h"
+#include "src/core/lib/security/credentials/fake/fake_credentials.h"
+#include "src/core/lib/security/transport/lb_targets_info.h"
 #include "src/core/lib/security/transport/secure_endpoint.h"
 #include "src/core/lib/security/transport/security_handshaker.h"
 #include "src/core/lib/support/env.h"
@@ -205,23 +208,23 @@ static const grpc_arg_pointer_vtable connector_pointer_vtable = {
 grpc_arg grpc_security_connector_to_arg(grpc_security_connector *sc) {
   grpc_arg result;
   result.type = GRPC_ARG_POINTER;
-  result.key = GRPC_SECURITY_CONNECTOR_ARG;
+  result.key = GRPC_ARG_SECURITY_CONNECTOR;
   result.value.pointer.vtable = &connector_pointer_vtable;
   result.value.pointer.p = sc;
   return result;
 }
 
 grpc_security_connector *grpc_security_connector_from_arg(const grpc_arg *arg) {
-  if (strcmp(arg->key, GRPC_SECURITY_CONNECTOR_ARG)) return NULL;
+  if (strcmp(arg->key, GRPC_ARG_SECURITY_CONNECTOR)) return NULL;
   if (arg->type != GRPC_ARG_POINTER) {
     gpr_log(GPR_ERROR, "Invalid type %d for arg %s", arg->type,
-            GRPC_SECURITY_CONNECTOR_ARG);
+            GRPC_ARG_SECURITY_CONNECTOR);
     return NULL;
   }
   return arg->value.pointer.p;
 }
 
-grpc_security_connector *grpc_find_security_connector_in_args(
+grpc_security_connector *grpc_security_connector_find_in_args(
     const grpc_channel_args *args) {
   size_t i;
   if (args == NULL) return NULL;
@@ -235,11 +238,21 @@ grpc_security_connector *grpc_find_security_connector_in_args(
 
 /* -- Fake implementation. -- */
 
+typedef struct {
+  grpc_channel_security_connector base;
+  char *target;
+  char *expected_targets;
+  bool is_lb_channel;
+} grpc_fake_channel_security_connector;
+
 static void fake_channel_destroy(grpc_exec_ctx *exec_ctx,
                                  grpc_security_connector *sc) {
-  grpc_channel_security_connector *c = (grpc_channel_security_connector *)sc;
-  grpc_call_credentials_unref(exec_ctx, c->request_metadata_creds);
-  gpr_free(sc);
+  grpc_fake_channel_security_connector *c =
+      (grpc_fake_channel_security_connector *)sc;
+  grpc_call_credentials_unref(exec_ctx, c->base.request_metadata_creds);
+  gpr_free(c->target);
+  gpr_free(c->expected_targets);
+  gpr_free(c);
 }
 
 static void fake_server_destroy(grpc_exec_ctx *exec_ctx,
@@ -247,6 +260,68 @@ static void fake_server_destroy(grpc_exec_ctx *exec_ctx,
   gpr_free(sc);
 }
 
+static bool fake_check_target(const char *target_type, const char *target,
+                              const char *set_str) {
+  GPR_ASSERT(target_type != NULL);
+  GPR_ASSERT(target != NULL);
+  char **set = NULL;
+  size_t set_size = 0;
+  gpr_string_split(set_str, ",", &set, &set_size);
+  bool found = false;
+  for (size_t i = 0; i < set_size; ++i) {
+    if (set[i] != NULL && strcmp(target, set[i]) == 0) found = true;
+  }
+  for (size_t i = 0; i < set_size; ++i) {
+    gpr_free(set[i]);
+  }
+  gpr_free(set);
+  return found;
+}
+
+static void fake_secure_name_check(const char *target,
+                                   const char *expected_targets,
+                                   bool is_lb_channel) {
+  if (expected_targets == NULL) return;
+  char **lbs_and_backends = NULL;
+  size_t lbs_and_backends_size = 0;
+  bool success = false;
+  gpr_string_split(expected_targets, ";", &lbs_and_backends,
+                   &lbs_and_backends_size);
+  if (lbs_and_backends_size > 2 || lbs_and_backends_size == 0) {
+    gpr_log(GPR_ERROR, "Invalid expected targets arg value: '%s'",
+            expected_targets);
+    goto done;
+  }
+  if (is_lb_channel) {
+    if (lbs_and_backends_size != 2) {
+      gpr_log(GPR_ERROR,
+              "Invalid expected targets arg value: '%s'. Expectations for LB "
+              "channels must be of the form 'be1,be2,be3,...;lb1,lb2,...",
+              expected_targets);
+      goto done;
+    }
+    if (!fake_check_target("LB", target, lbs_and_backends[1])) {
+      gpr_log(GPR_ERROR, "LB target '%s' not found in expected set '%s'",
+              target, lbs_and_backends[1]);
+      goto done;
+    }
+    success = true;
+  } else {
+    if (!fake_check_target("Backend", target, lbs_and_backends[0])) {
+      gpr_log(GPR_ERROR, "Backend target '%s' not found in expected set '%s'",
+              target, lbs_and_backends[0]);
+      goto done;
+    }
+    success = true;
+  }
+done:
+  for (size_t i = 0; i < lbs_and_backends_size; ++i) {
+    gpr_free(lbs_and_backends[i]);
+  }
+  gpr_free(lbs_and_backends);
+  if (!success) abort();
+}
+
 static void fake_check_peer(grpc_exec_ctx *exec_ctx,
                             grpc_security_connector *sc, tsi_peer peer,
                             grpc_auth_context **auth_context,
@@ -277,12 +352,28 @@ static void fake_check_peer(grpc_exec_ctx *exec_ctx,
   grpc_auth_context_add_cstring_property(
       *auth_context, GRPC_TRANSPORT_SECURITY_TYPE_PROPERTY_NAME,
       GRPC_FAKE_TRANSPORT_SECURITY_TYPE);
-
 end:
   grpc_closure_sched(exec_ctx, on_peer_checked, error);
   tsi_peer_destruct(&peer);
 }
 
+static void fake_channel_check_peer(grpc_exec_ctx *exec_ctx,
+                                    grpc_security_connector *sc, tsi_peer peer,
+                                    grpc_auth_context **auth_context,
+                                    grpc_closure *on_peer_checked) {
+  fake_check_peer(exec_ctx, sc, peer, auth_context, on_peer_checked);
+  grpc_fake_channel_security_connector *c =
+      (grpc_fake_channel_security_connector *)sc;
+  fake_secure_name_check(c->target, c->expected_targets, c->is_lb_channel);
+}
+
+static void fake_server_check_peer(grpc_exec_ctx *exec_ctx,
+                                   grpc_security_connector *sc, tsi_peer peer,
+                                   grpc_auth_context **auth_context,
+                                   grpc_closure *on_peer_checked) {
+  fake_check_peer(exec_ctx, sc, peer, auth_context, on_peer_checked);
+}
+
 static void fake_channel_check_call_host(grpc_exec_ctx *exec_ctx,
                                          grpc_channel_security_connector *sc,
                                          const char *host,
@@ -313,22 +404,32 @@ static void fake_server_add_handshakers(grpc_exec_ctx *exec_ctx,
 }
 
 static grpc_security_connector_vtable fake_channel_vtable = {
-    fake_channel_destroy, fake_check_peer};
+    fake_channel_destroy, fake_channel_check_peer};
 
-static grpc_security_connector_vtable fake_server_vtable = {fake_server_destroy,
-                                                            fake_check_peer};
+static grpc_security_connector_vtable fake_server_vtable = {
+    fake_server_destroy, fake_server_check_peer};
 
 grpc_channel_security_connector *grpc_fake_channel_security_connector_create(
-    grpc_call_credentials *request_metadata_creds) {
-  grpc_channel_security_connector *c = gpr_malloc(sizeof(*c));
+    grpc_call_credentials *request_metadata_creds, const char *target,
+    const grpc_channel_args *args) {
+  grpc_fake_channel_security_connector *c = gpr_malloc(sizeof(*c));
   memset(c, 0, sizeof(*c));
-  gpr_ref_init(&c->base.refcount, 1);
-  c->base.url_scheme = GRPC_FAKE_SECURITY_URL_SCHEME;
-  c->base.vtable = &fake_channel_vtable;
-  c->request_metadata_creds = grpc_call_credentials_ref(request_metadata_creds);
-  c->check_call_host = fake_channel_check_call_host;
-  c->add_handshakers = fake_channel_add_handshakers;
-  return c;
+  gpr_ref_init(&c->base.base.refcount, 1);
+  c->base.base.url_scheme = GRPC_FAKE_SECURITY_URL_SCHEME;
+  c->base.base.vtable = &fake_channel_vtable;
+  c->base.request_metadata_creds =
+      grpc_call_credentials_ref(request_metadata_creds);
+  c->base.check_call_host = fake_channel_check_call_host;
+  c->base.add_handshakers = fake_channel_add_handshakers;
+  c->target = gpr_strdup(target);
+  const grpc_arg *expected_target_arg =
+      grpc_channel_args_find(args, GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS);
+  if (expected_target_arg != NULL) {
+    GPR_ASSERT(expected_target_arg->type == GRPC_ARG_STRING);
+    c->expected_targets = gpr_strdup(expected_target_arg->value.string);
+  }
+  c->is_lb_channel = (grpc_lb_targets_info_find_in_args(args) != NULL);
+  return &c->base;
 }
 
 grpc_server_security_connector *grpc_fake_server_security_connector_create(

src/core/lib/security/transport/security_connector.h

@@ -57,7 +57,7 @@ typedef enum { GRPC_SECURITY_OK = 0, GRPC_SECURITY_ERROR } grpc_security_status;
 
 typedef struct grpc_security_connector grpc_security_connector;
 
-#define GRPC_SECURITY_CONNECTOR_ARG "grpc.security_connector"
+#define GRPC_ARG_SECURITY_CONNECTOR "grpc.security_connector"
 
 typedef struct {
   void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_security_connector *sc);
@@ -115,7 +115,7 @@ grpc_arg grpc_security_connector_to_arg(grpc_security_connector *sc);
 grpc_security_connector *grpc_security_connector_from_arg(const grpc_arg *arg);
 
 /* Util to find the connector from channel args. */
-grpc_security_connector *grpc_find_security_connector_in_args(
+grpc_security_connector *grpc_security_connector_find_in_args(
     const grpc_channel_args *args);
 
 /* --- channel_security_connector object. ---
@@ -175,7 +175,8 @@ void grpc_server_security_connector_add_handshakers(
 /* For TESTING ONLY!
    Creates a fake connector that emulates real channel security.  */
 grpc_channel_security_connector *grpc_fake_channel_security_connector_create(
-    grpc_call_credentials *request_metadata_creds);
+    grpc_call_credentials *request_metadata_creds, const char *target,
+    const grpc_channel_args *args);
 
 /* For TESTING ONLY!
    Creates a fake connector that emulates real server security.  */

src/core/lib/security/transport/security_handshaker.c

@@ -451,7 +451,7 @@ static void client_handshaker_factory_add_handshakers(
     grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory,
     const grpc_channel_args *args, grpc_handshake_manager *handshake_mgr) {
   grpc_channel_security_connector *security_connector =
-      (grpc_channel_security_connector *)grpc_find_security_connector_in_args(
+      (grpc_channel_security_connector *)grpc_security_connector_find_in_args(
           args);
   grpc_channel_security_connector_add_handshakers(exec_ctx, security_connector,
                                                   handshake_mgr);
@@ -461,7 +461,7 @@ static void server_handshaker_factory_add_handshakers(
     grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *hf,
     const grpc_channel_args *args, grpc_handshake_manager *handshake_mgr) {
   grpc_server_security_connector *security_connector =
-      (grpc_server_security_connector *)grpc_find_security_connector_in_args(
+      (grpc_server_security_connector *)grpc_security_connector_find_in_args(
           args);
   grpc_server_security_connector_add_handshakers(exec_ctx, security_connector,
                                                  handshake_mgr);

src/core/lib/slice/slice_intern.c

@@ -215,7 +215,9 @@ bool grpc_slice_is_interned(grpc_slice slice) {
 }
 
 grpc_slice grpc_slice_intern(grpc_slice slice) {
+  GPR_TIMER_BEGIN("grpc_slice_intern", 0);
   if (GRPC_IS_STATIC_METADATA_STRING(slice)) {
+    GPR_TIMER_END("grpc_slice_intern", 0);
     return slice;
   }
 
@@ -225,6 +227,7 @@ grpc_slice grpc_slice_intern(grpc_slice slice) {
         static_metadata_hash[(hash + i) % GPR_ARRAY_SIZE(static_metadata_hash)];
     if (ent.hash == hash && ent.idx < GRPC_STATIC_MDSTR_COUNT &&
         grpc_slice_eq(grpc_static_slice_table[ent.idx], slice)) {
+      GPR_TIMER_END("grpc_slice_intern", 0);
       return grpc_static_slice_table[ent.idx];
     }
   }
@@ -247,7 +250,7 @@ grpc_slice grpc_slice_intern(grpc_slice slice) {
         /* and treat this as if we were never here... sshhh */
       } else {
         gpr_mu_unlock(&shard->mu);
-        GPR_TIMER_END("grpc_mdstr_from_buffer", 0);
+        GPR_TIMER_END("grpc_slice_intern", 0);
         return materialize(s);
       }
     }
@@ -275,6 +278,7 @@ grpc_slice grpc_slice_intern(grpc_slice slice) {
 
   gpr_mu_unlock(&shard->mu);
 
+  GPR_TIMER_END("grpc_slice_intern", 0);
   return materialize(s);
 }
 

src/core/lib/support/log_posix.c

@@ -37,6 +37,7 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 #include <pthread.h>
 #include <stdarg.h>
@@ -93,10 +94,13 @@ void gpr_default_log(gpr_log_func_args *args) {
     strcpy(time_buffer, "error:strftime");
   }
 
-  fprintf(stderr, "%s%s.%09d %7tu %s:%d] %s\n",
-          gpr_log_severity_string(args->severity), time_buffer,
-          (int)(now.tv_nsec), gettid(), display_file, args->line,
-          args->message);
+  char *prefix;
+  gpr_asprintf(&prefix, "%s%s.%09d %7tu %s:%d]",
+               gpr_log_severity_string(args->severity), time_buffer,
+               (int)(now.tv_nsec), gettid(), display_file, args->line);
+
+  fprintf(stderr, "%-70s %s\n", prefix, args->message);
+  gpr_free(prefix);
 }
 
 #endif /* defined(GPR_POSIX_LOG) */

src/core/lib/support/sync_posix.c

@@ -42,11 +42,18 @@
 #include <time.h>
 #include "src/core/lib/profiling/timers.h"
 
+#ifdef GPR_MU_COUNTERS
+gpr_atm grpc_mu_locks = 0;
+#endif
+
 void gpr_mu_init(gpr_mu* mu) { GPR_ASSERT(pthread_mutex_init(mu, NULL) == 0); }
 
 void gpr_mu_destroy(gpr_mu* mu) { GPR_ASSERT(pthread_mutex_destroy(mu) == 0); }
 
 void gpr_mu_lock(gpr_mu* mu) {
+#ifdef GPR_MU_COUNTERS
+  gpr_atm_no_barrier_fetch_add(&grpc_mu_locks, 1);
+#endif
   GPR_TIMER_BEGIN("gpr_mu_lock", 0);
   GPR_ASSERT(pthread_mutex_lock(mu) == 0);
   GPR_TIMER_END("gpr_mu_lock", 0);

src/core/lib/support/time_windows.c

@@ -56,7 +56,7 @@ void gpr_time_init(void) {
   g_time_scale = 1.0 / (double)frequency.QuadPart;
 }
 
-gpr_timespec gpr_now(gpr_clock_type clock) {
+static gpr_timespec now_impl(gpr_clock_type clock) {
   gpr_timespec now_tv;
   LONGLONG diff;
   struct _timeb now_tb;
@@ -84,6 +84,12 @@ gpr_timespec gpr_now(gpr_clock_type clock) {
   return now_tv;
 }
 
+gpr_timespec (*gpr_now_impl)(gpr_clock_type clock_type) = now_impl;
+
+gpr_timespec gpr_now(gpr_clock_type clock_type) {
+  return gpr_now_impl(clock_type);
+}
+
 void gpr_sleep_until(gpr_timespec until) {
   gpr_timespec now;
   gpr_timespec delta;

src/core/lib/surface/call.c

@@ -86,8 +86,11 @@ typedef enum {
   /* Status came from 'the wire' - or somewhere below the surface
      layer */
   STATUS_FROM_WIRE,
-  /* Status was created by some internal channel stack operation */
+  /* Status was created by some internal channel stack operation: must come via
+     add_batch_error */
   STATUS_FROM_CORE,
+  /* Status was created by some surface error */
+  STATUS_FROM_SURFACE,
   /* Status came from the server sending status */
   STATUS_FROM_SERVER_STATUS,
   STATUS_SOURCE_COUNT
@@ -212,6 +215,8 @@ struct grpc_call {
   void *saved_receiving_stream_ready_bctlp;
 };
 
+int grpc_call_error_trace = 0;
+
 #define CALL_STACK_FROM_CALL(call) ((grpc_call_stack *)((call) + 1))
 #define CALL_FROM_CALL_STACK(call_stack) (((grpc_call *)(call_stack)) - 1)
 #define CALL_ELEM_FROM_CALL(call, idx) \
@@ -221,11 +226,11 @@ struct grpc_call {
 
 static void execute_op(grpc_exec_ctx *exec_ctx, grpc_call *call,
                        grpc_transport_stream_op *op);
-static grpc_call_error cancel_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
-                                          grpc_status_code status,
-                                          const char *description);
+static void cancel_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
+                               status_source source, grpc_status_code status,
+                               const char *description);
 static void cancel_with_error(grpc_exec_ctx *exec_ctx, grpc_call *c,
-                              grpc_error *error);
+                              status_source source, grpc_error *error);
 static void destroy_call(grpc_exec_ctx *exec_ctx, void *call_stack,
                          grpc_error *error);
 static void receiving_slice_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
@@ -352,7 +357,8 @@ grpc_error *grpc_call_create(grpc_exec_ctx *exec_ctx,
                                               call->start_time, send_deadline,
                                               CALL_STACK_FROM_CALL(call)));
   if (error != GRPC_ERROR_NONE) {
-    cancel_with_error(exec_ctx, call, GRPC_ERROR_REF(error));
+    cancel_with_error(exec_ctx, call, STATUS_FROM_SURFACE,
+                      GRPC_ERROR_REF(error));
   }
   if (args->cq != NULL) {
     GPR_ASSERT(
@@ -527,7 +533,6 @@ grpc_call_error grpc_call_cancel_with_status(grpc_call *c,
                                              grpc_status_code status,
                                              const char *description,
                                              void *reserved) {
-  grpc_call_error r;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   GRPC_API_TRACE(
       "grpc_call_cancel_with_status("
@@ -535,16 +540,16 @@ grpc_call_error grpc_call_cancel_with_status(grpc_call *c,
       4, (c, (int)status, description, reserved));
   GPR_ASSERT(reserved == NULL);
   gpr_mu_lock(&c->mu);
-  r = cancel_with_status(&exec_ctx, c, status, description);
+  cancel_with_status(&exec_ctx, c, STATUS_FROM_API_OVERRIDE, status,
+                     description);
   gpr_mu_unlock(&c->mu);
   grpc_exec_ctx_finish(&exec_ctx);
-  return r;
+  return GRPC_CALL_OK;
 }
 
 typedef struct termination_closure {
   grpc_closure closure;
   grpc_call *call;
-  grpc_error *error;
   grpc_transport_stream_op op;
 } termination_closure;
 
@@ -559,36 +564,27 @@ static void send_termination(grpc_exec_ctx *exec_ctx, void *tcp,
                              grpc_error *error) {
   termination_closure *tc = tcp;
   memset(&tc->op, 0, sizeof(tc->op));
-  tc->op.cancel_error = tc->error;
+  tc->op.cancel_error = GRPC_ERROR_REF(error);
   /* reuse closure to catch completion */
-  grpc_closure_init(&tc->closure, done_termination, tc,
-                    grpc_schedule_on_exec_ctx);
-  tc->op.on_complete = &tc->closure;
+  tc->op.on_complete = grpc_closure_init(&tc->closure, done_termination, tc,
+                                         grpc_schedule_on_exec_ctx);
   execute_op(exec_ctx, tc->call, &tc->op);
 }
 
-static grpc_call_error terminate_with_status(grpc_exec_ctx *exec_ctx,
-                                             termination_closure *tc) {
-  set_status_from_error(exec_ctx, tc->call, STATUS_FROM_API_OVERRIDE,
-                        GRPC_ERROR_REF(tc->error));
-  grpc_closure_init(&tc->closure, send_termination, tc,
-                    grpc_schedule_on_exec_ctx);
-  GRPC_CALL_INTERNAL_REF(tc->call, "termination");
-  grpc_closure_sched(exec_ctx, &tc->closure, GRPC_ERROR_NONE);
-  return GRPC_CALL_OK;
-}
-
-static grpc_call_error terminate_with_error(grpc_exec_ctx *exec_ctx,
-                                            grpc_call *c, grpc_error *error) {
+static void terminate_with_error(grpc_exec_ctx *exec_ctx, grpc_call *c,
+                                 grpc_error *error) {
   termination_closure *tc = gpr_malloc(sizeof(*tc));
   memset(tc, 0, sizeof(*tc));
   tc->call = c;
-  tc->error = error;
-  return terminate_with_status(exec_ctx, tc);
+  GRPC_CALL_INTERNAL_REF(tc->call, "termination");
+  grpc_closure_sched(exec_ctx, grpc_closure_init(&tc->closure, send_termination,
+                                                 tc, grpc_schedule_on_exec_ctx),
+                     error);
 }
 
 static void cancel_with_error(grpc_exec_ctx *exec_ctx, grpc_call *c,
-                              grpc_error *error) {
+                              status_source source, grpc_error *error) {
+  set_status_from_error(exec_ctx, c, source, GRPC_ERROR_REF(error));
   terminate_with_error(exec_ctx, c, error);
 }
 
@@ -600,32 +596,35 @@ static grpc_error *error_from_status(grpc_status_code status,
       GRPC_ERROR_INT_GRPC_STATUS, status);
 }
 
-static grpc_call_error cancel_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
-                                          grpc_status_code status,
-                                          const char *description) {
-  return terminate_with_error(exec_ctx, c,
-                              error_from_status(status, description));
+static void cancel_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
+                               status_source source, grpc_status_code status,
+                               const char *description) {
+  cancel_with_error(exec_ctx, c, source,
+                    error_from_status(status, description));
 }
 
 /*******************************************************************************
  * FINAL STATUS CODE MANIPULATION
  */
 
-static void get_final_status_from(grpc_call *call, status_source from_source,
-                                  void (*set_value)(grpc_status_code code,
-                                                    void *user_data),
-                                  void *set_value_user_data,
-                                  grpc_slice *details) {
+static bool get_final_status_from(
+    grpc_call *call, status_source from_source, bool allow_ok_status,
+    void (*set_value)(grpc_status_code code, void *user_data),
+    void *set_value_user_data, grpc_slice *details) {
   grpc_status_code code;
   const char *msg = NULL;
   grpc_error_get_status(call->status[from_source].error, call->send_deadline,
                         &code, &msg, NULL);
+  if (code == GRPC_STATUS_OK && !allow_ok_status) {
+    return false;
+  }
 
   set_value(code, set_value_user_data);
   if (details != NULL) {
     *details =
         msg == NULL ? grpc_empty_slice() : grpc_slice_from_copied_string(msg);
   }
+  return true;
 }
 
 static void get_final_status(grpc_call *call,
@@ -633,22 +632,37 @@ static void get_final_status(grpc_call *call,
                                                void *user_data),
                              void *set_value_user_data, grpc_slice *details) {
   int i;
-  /* search for the best status we can present: ideally the error we use has a
-     clearly defined grpc-status, and we'll prefer that. */
-  for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
-    if (call->status[i].is_set &&
-        grpc_error_has_clear_grpc_status(call->status[i].error)) {
-      get_final_status_from(call, (status_source)i, set_value,
-                            set_value_user_data, details);
-      return;
+  if (grpc_call_error_trace) {
+    gpr_log(GPR_DEBUG, "get_final_status %s", call->is_client ? "CLI" : "SVR");
+    for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
+      if (call->status[i].is_set) {
+        gpr_log(GPR_DEBUG, "  %d: %s", i,
+                grpc_error_string(call->status[i].error));
+      }
     }
   }
-  /* If no clearly defined status exists, search for 'anything' */
-  for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
-    if (call->status[i].is_set) {
-      get_final_status_from(call, (status_source)i, set_value,
-                            set_value_user_data, details);
-      return;
+  /* first search through ignoring "OK" statuses: if something went wrong,
+   * ensure we report it */
+  for (int allow_ok_status = 0; allow_ok_status < 2; allow_ok_status++) {
+    /* search for the best status we can present: ideally the error we use has a
+       clearly defined grpc-status, and we'll prefer that. */
+    for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
+      if (call->status[i].is_set &&
+          grpc_error_has_clear_grpc_status(call->status[i].error)) {
+        if (get_final_status_from(call, (status_source)i, allow_ok_status != 0,
+                                  set_value, set_value_user_data, details)) {
+          return;
+        }
+      }
+    }
+    /* If no clearly defined status exists, search for 'anything' */
+    for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
+      if (call->status[i].is_set) {
+        if (get_final_status_from(call, (status_source)i, allow_ok_status != 0,
+                                  set_value, set_value_user_data, details)) {
+          return;
+        }
+      }
     }
   }
   /* If nothing exists, set some default */
@@ -883,7 +897,7 @@ static void recv_common_filter(grpc_exec_ctx *exec_ctx, grpc_call *call,
       error = grpc_error_set_str(error, GRPC_ERROR_STR_GRPC_MESSAGE, msg);
       gpr_free(msg);
       grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.grpc_message);
-    } else {
+    } else if (error != GRPC_ERROR_NONE) {
       error = grpc_error_set_str(error, GRPC_ERROR_STR_GRPC_MESSAGE, "");
     }
 
@@ -1029,11 +1043,6 @@ static void post_batch_completion(grpc_exec_ctx *exec_ctx,
 
   gpr_mu_lock(&call->mu);
 
-  if (error != GRPC_ERROR_NONE) {
-    set_status_from_error(exec_ctx, call, STATUS_FROM_CORE,
-                          GRPC_ERROR_REF(error));
-  }
-
   if (bctl->send_initial_metadata) {
     grpc_metadata_batch_destroy(
         exec_ctx,
@@ -1176,7 +1185,8 @@ static void receiving_stream_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
   grpc_call *call = bctl->call;
   gpr_mu_lock(&bctl->call->mu);
   if (error != GRPC_ERROR_NONE) {
-    cancel_with_error(exec_ctx, call, GRPC_ERROR_REF(error));
+    cancel_with_error(exec_ctx, call, STATUS_FROM_SURFACE,
+                      GRPC_ERROR_REF(error));
   }
   if (call->has_initial_md_been_received || error != GRPC_ERROR_NONE ||
       call->receiving_stream == NULL) {
@@ -1203,7 +1213,8 @@ static void validate_filtered_metadata(grpc_exec_ctx *exec_ctx,
       gpr_asprintf(&error_msg, "Invalid compression algorithm value '%d'.",
                    algo);
       gpr_log(GPR_ERROR, "%s", error_msg);
-      cancel_with_status(exec_ctx, call, GRPC_STATUS_UNIMPLEMENTED, error_msg);
+      cancel_with_status(exec_ctx, call, STATUS_FROM_SURFACE,
+                         GRPC_STATUS_UNIMPLEMENTED, error_msg);
     } else if (grpc_compression_options_is_algorithm_enabled(
                    &compression_options, algo) == 0) {
       /* check if algorithm is supported by current channel config */
@@ -1212,7 +1223,8 @@ static void validate_filtered_metadata(grpc_exec_ctx *exec_ctx,
       gpr_asprintf(&error_msg, "Compression algorithm '%s' is disabled.",
                    algo_name);
       gpr_log(GPR_ERROR, "%s", error_msg);
-      cancel_with_status(exec_ctx, call, GRPC_STATUS_UNIMPLEMENTED, error_msg);
+      cancel_with_status(exec_ctx, call, STATUS_FROM_SURFACE,
+                         GRPC_STATUS_UNIMPLEMENTED, error_msg);
     } else {
       call->incoming_compression_algorithm = algo;
     }
@@ -1242,7 +1254,10 @@ static void add_batch_error(grpc_exec_ctx *exec_ctx, batch_control *bctl,
                             grpc_error *error) {
   if (error == GRPC_ERROR_NONE) return;
   int idx = (int)gpr_atm_no_barrier_fetch_add(&bctl->num_errors, 1);
-  if (idx == 0) cancel_with_error(exec_ctx, bctl->call, GRPC_ERROR_REF(error));
+  if (idx == 0) {
+    cancel_with_error(exec_ctx, bctl->call, STATUS_FROM_CORE,
+                      GRPC_ERROR_REF(error));
+  }
   bctl->errors[idx] = error;
 }
 
@@ -1468,6 +1483,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         }
         bctl->send_final_op = 1;
         call->sent_final_op = 1;
+        GPR_ASSERT(call->send_extra_metadata_count == 0);
         call->send_extra_metadata_count = 1;
         call->send_extra_metadata[0].md = grpc_channel_get_reffed_status_elem(
             exec_ctx, call->channel, op->data.send_status_from_server.status);
@@ -1496,6 +1512,10 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
                 (int)op->data.send_status_from_server.trailing_metadata_count,
                 op->data.send_status_from_server.trailing_metadata, 1, 1, NULL,
                 0)) {
+          for (int n = 0; n < call->send_extra_metadata_count; n++) {
+            GRPC_MDELEM_UNREF(exec_ctx, call->send_extra_metadata[n].md);
+          }
+          call->send_extra_metadata_count = 0;
           error = GRPC_CALL_ERROR_INVALID_METADATA;
           goto done_with_error;
         }